EJB - thread pool fills up until no connection possible

Hi,

We use JBoss EAP 6.4.6 for our middleware and frontend servers. They are communicating with ejb-remote.

In the last months we are struggeling with the problem that sometimes the whole system gets unresponsive after the ejb remote pool is filling up to the maxThreads value.

The problem sounds really similar to this issue https://access.redhat.com/solutions/1223983. We also get a lot of timeout messages while the pool starts to fill up and we can see similiar call stacks in Dynatrace.
<img src="/sites/profiles/files/discussion/images/2017-09/20170516_callstack.png" width="1409" height="618" alt="" />

When the pool is full we also can see messages like this:

javax.ejb.EJBException: java.io.IOException: Channel Channel ID b6f8de2d (outbound) of Remoting connection 2f5fbc16 to /22.161.73.65:4447 has been closed

and

JBAS014559: Invocation cannot proceed as component is shutting down

Is somebody of you aware if there is another issue similiar to the one I mentioned above, but for version 6.4.6?

regards,
Gerald