The fixes introduced as a part of https://issues.jboss.org/browse/JWS-1028 are not incorporated for use case when KIE server is deployed to Tomcat.

jBPM embedded uses:
https://github.com/web-servers/narayana-tomcat/blob/master/tomcat-jta/src/main/java/org/jboss/narayana/tomcat/jta/PoolingDataSource.java

while for Tomcat, context.xml defines a factory bean providing the datasource:
https://github.com/web-servers/narayana-tomcat/blob/master/tomcat-jta/src/main/java/org/jboss/narayana/tomcat/jta/TransactionalDataSourceFactory.java

As you see, the TransactionalDataSourceFactory impl differs from the PoolingDataSource and doesn't use DataSourceXAConnectionFactory, which has been updated with a constructors taking a TransactionSynchronizationRegistry reference. This is the fix that for the issue in embedded use case. Now we need to take it into this TransactionalDataSourceFactory to make it effective for tomcat integration scenarios