This does not seem to be isolated to Firefox I'm afraid.
I've attached the log snippet to this reply.
If it helps we have also noticed that we receive the following errors in the logs
- Accept error on socket Lightstreamer HTTP Server java.io.IOException: Too many open files
- Failure in request processing: Bad request: com.lightstreamer.b.c: It was expected an integer value for LS_polling_millis
- Bad request: It was expected an integer value for LS_polling_millis
- Sync error: Can't find session from ...
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