The TX datasource shell script does not have any validate-on-match setting configured.
This in conjunction with no idle-timeout-minutes setting is a cause for a brittle database failover.
If these settings were not customly added you would not recover from a database failover
Why - the datasource connection would not be validated on match and hence would continue to get requests thus not being set as idle.
Once the validation has been added then the datasource connection will become idle following a database failover. The default idle timeout if not specified is 30minutes.