Still "There are still SSE events the queue which may not be delivered (closing now)" in OH 3.3-SNAPSHOT

Hi,
after a relative smooth and successful migration from 2.5 to 3.3-SNAPSHOT I still have these

There are still SSE events the queue which may not be delivered (closing now)

in my log file.
I have the suspicion, that they are realated to the Z-Wave binding, as the events seem to happen in conjunction with zwave events.
I searched in the forum but realized, that the newest entry
there-are-still-sse-events-the-queue
hasen’t been aswered yet.
Is there anything I can do to dig a little deeper into this issue?
Thanks Joerg