8.12.x is currently dependent on resteasy-jaxrs:jar:2.3.7.Final
In upgrading the IP-BOM to 30, which is dependent on 2.3.10, it seems the following class has been removed from javax-rs 2.3.10:
org/jboss/resteasy/util/HttpServletRequestDelegate.java
which breaks ProxyHttpServletRequest.java