The connection is registered here:

2024-02-27 12:22:57,638 TRACE [org.jboss.jca.core.connectionmanager.listener.TxConnectionListener] (default task-1) [TxConnectionListener@36c4cf49] registerConnection: org.jboss.jca.adapters.jdbc.jdk8.WrappedConnectionJDK8@54bf484 [size=1] ([org.jboss.jca.adapters.jdbc.jdk8.WrappedConnectionJDK8@54bf484])
2024-02-27 12:22:57,638 TRACE [org.jboss.jca.core.api.connectionmanager.ccm.CachedConnectionManager] (default task-1) registering connection from connection manager: org.jboss.jca.core.connectionmanager.tx.TxConnectionManagerImpl@1d77a1cc, connection : org.jboss.jca.adapters.jdbc.jdk8.WrappedConnectionJDK8@54bf484, key: org.jboss.as.connector.deployers.ra.processors.CachedConnectionManagerSetupProcessor$CachedConnectionManagerSetupAction@699b624e
2024-02-27 12:22:57,638 TRACE [org.jboss.jca.core.tracer.Tracer] (default task-1) IJTRACER-redactedDS-63bafac7-401-92-70126416719000-36c4cf49-54bf484-org.jboss.as.connector.deployers.ra.processors.CachedConnectionManagerSetupProcessor$CachedConnectionManagerSetupAction@699b624e

And unregistered here. There are no other connections registered in between!

2024-02-27 12:22:57,995 DEBUG [org.hibernate.id.enhanced.SequenceStructure] (default task-1) Sequence value obtained: 10558
2024-02-27 12:22:57,995 TRACE [org.hibernate.resource.jdbc.internal.ResourceRegistryStandardImpl] (default task-1) Releasing result set [SQLServerResultSet:1360]
2024-02-27 12:22:57,995 TRACE [org.hibernate.resource.jdbc.internal.ResourceRegistryStandardImpl] (default task-1) Closing result set [SQLServerResultSet:1360]
2024-02-27 12:22:57,995 TRACE [org.hibernate.resource.jdbc.internal.ResourceRegistryStandardImpl] (default task-1) Releasing statement [org.jboss.jca.adapters.jdbc.jdk8.WrappedPreparedStatementJDK8@1464acba]
2024-02-27 12:22:57,995 TRACE [org.hibernate.resource.jdbc.internal.ResourceRegistryStandardImpl] (default task-1) Closing prepared statement [org.jboss.jca.adapters.jdbc.jdk8.WrappedPreparedStatementJDK8@1464acba]
2024-02-27 12:22:57,995 TRACE [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (default task-1) Lock: HeldByCurrentThread: No, Locked: No, HoldCount: 0, QueueLength: 0
2024-02-27 12:22:57,995 TRACE [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (default task-1) Unlock: HeldByCurrentThread: Yes, Locked: Yes, HoldCount: 1, QueueLength: 0
2024-02-27 12:22:57,996 TRACE [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (default task-1) Owner: Thread[default task-1,5,main]
2024-02-27 12:22:57,996 TRACE [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (default task-1) Lock: HeldByCurrentThread: No, Locked: No, HoldCount: 0, QueueLength: 0
2024-02-27 12:22:57,996 TRACE [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (default task-1) Unlock: HeldByCurrentThread: Yes, Locked: Yes, HoldCount: 1, QueueLength: 0
2024-02-27 12:22:57,996 TRACE [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (default task-1) Owner: Thread[default task-1,5,main]
2024-02-27 12:22:57,996 TRACE [org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl] (default task-1) Starting after statement execution processing [AFTER_STATEMENT]
2024-02-27 12:22:57,996 TRACE [org.hibernate.resource.jdbc.internal.AbstractLogicalConnectionImplementor] (default task-1) LogicalConnection#afterStatement
2024-02-27 12:22:57,996 DEBUG [org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl] (default task-1) Initiating JDBC connection release from afterStatement
2024-02-27 12:22:57,996 TRACE [org.hibernate.resource.jdbc.internal.ResourceRegistryStandardImpl] (default task-1) Releasing JDBC resources
2024-02-27 12:22:57,996 DEBUG [org.hibernate.orm.jdbc.batch] (default task-1) PreparedStatementDetails did not contain PreparedStatement on #releaseStatements : insert into [...]
2024-02-27 12:22:57,996 TRACE [org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl] (default task-1) Starting after statement execution processing [AFTER_STATEMENT]
2024-02-27 12:22:57,996 TRACE [org.hibernate.resource.jdbc.internal.AbstractLogicalConnectionImplementor] (default task-1) LogicalConnection#afterStatement
2024-02-27 12:22:57,996 DEBUG [org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl] (default task-1) Initiating JDBC connection release from afterStatement
2024-02-27 12:22:57,996 TRACE [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (default task-1) Lock: HeldByCurrentThread: No, Locked: No, HoldCount: 0, QueueLength: 0
2024-02-27 12:22:57,996 TRACE [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (default task-1) Unlock: HeldByCurrentThread: Yes, Locked: Yes, HoldCount: 1, QueueLength: 0
2024-02-27 12:22:57,996 TRACE [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (default task-1) Owner: Thread[default task-1,5,main]
2024-02-27 12:22:57,996 TRACE [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (default task-1) Lock: HeldByCurrentThread: No, Locked: No, HoldCount: 0, QueueLength: 0
2024-02-27 12:22:57,996 TRACE [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (default task-1) Unlock: HeldByCurrentThread: Yes, Locked: Yes, HoldCount: 1, QueueLength: 0
2024-02-27 12:22:57,996 TRACE [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (default task-1) Owner: Thread[default task-1,5,main]
2024-02-27 12:22:57,996 TRACE [org.jboss.jca.core.connectionmanager.listener.TxConnectionListener] (default task-1) connectionClosed called mc=org.jboss.jca.adapters.jdbc.local.LocalManagedConnection@25ae62a6
2024-02-27 12:22:57,996 TRACE [org.jboss.jca.core.api.connectionmanager.ccm.CachedConnectionManager] (default task-1) unregistering connection from connection manager: org.jboss.jca.core.connectionmanager.tx.TxConnectionManagerImpl@1d77a1cc, connection: org.jboss.jca.adapters.jdbc.jdk8.WrappedConnectionJDK8@54bf484, key: org.jboss.as.connector.deployers.ra.processors.CachedConnectionManagerSetupProcessor$CachedConnectionManagerSetupAction@699b624e
2024-02-27 12:22:57,996 TRACE [org.jboss.jca.core.tracer.Tracer] (default task-1) IJTRACER-redactedDS-63bafac7-401-95-70126775236799-36c4cf49-54bf484-org.jboss.as.connector.deployers.ra.processors.CachedConnectionManagerSetupProcessor$CachedConnectionManagerSetupAction@699b624e
2024-02-27 12:22:57,996 INFO  [org.jboss.jca.core.connectionmanager.listener.TxConnectionListener] (default task-1) IJ000311: Throwable from unregister connection: java.lang.IllegalStateException: IJ000152: Trying to return an unknown connection: org.jboss.jca.adapters.jdbc.jdk8.WrappedConnectionJDK8@54bf484
[...]
2024-02-27 12:22:57,998 TRACE [org.jboss.jca.core.tracer.Tracer] (default task-1) IJTRACER-redactedDS-63bafac7-401-41-70126777019300-36c4cf49-54bf484-
2024-02-27 12:22:57,998 TRACE [org.jboss.jca.core.connectionmanager.listener.TxConnectionListener] (default task-1) [TxConnectionListener@36c4cf49] unregisterConnection: 0 handles left ([])
2024-02-27 12:22:57,998 TRACE [org.jboss.jca.core.connectionmanager.listener.TxConnectionListener] (default task-1) isManagedConnectionFree=false mc=org.jboss.jca.adapters.jdbc.local.LocalManagedConnection@25ae62a6
2024-02-27 12:22:57,998 DEBUG [org.hibernate.event.internal.AbstractSaveEventListener] (default task-1) Generated identifier: 10539, using strategy: org.hibernate.id.enhanced.SequenceStyleGenerator
2024-02-27 12:22:57,998 TRACE [org.hibernate.event.internal.AbstractSaveEventListener] (default task-1) Saving [model.Entity#10539]
2024-02-27 12:22:57,998 TRACE [org.hibernate.engine.internal.Cascade] (default task-1) Processing cascade ACTION_PERSIST for: model.Entity