Asterisk error message astobj2.c: user_data is NULL

We have been getting this error message with great frequency as of late. We have upgraded to 1.8.21 and the issue has not been resolved.

We have it running in safe mode so it restarts but all calls are disconnected, as you might imagine.

Any suggestions would be appreciated. … +Backtrace

Note that memory management issues can be difficult to debug, as the fault may be some time before the crash.