I have. See KB ID:80464. Patch 6 is supposed to address this. There is also a workaround in the KB article. We had a lot of user sessions that would not drop off and we had to manually remove them. The root cause seemed to be that we were sending back XML that X3 gave to us, but it was causing a nextLong error. In our case, we were trying to change Sales Order and delivery dates.

Following up: Rather than modifying a SO, we are now deleting it and replacing with the same SO #.