The most likely causes are failures in ast_audiohook_attach, which seem to come down to either trying to do it on a channel that has already been hung up, or trying to do it when there is a critical shortage of memory. The latter is likely to result in many other errors.
If it were crashing, you would need to upgrade to Asterisk 18 or 20, before progressing the issue, as Asterisk 13 is over a year beyond end of life.
[quote=“david551, post:2, topic:95190”]
ast_audiohook_attach, which seem to come down to either trying to do it on a channel that has already been hung up[/quote]
possibly that’s it, because I can’t find the channel specified in the message in the logs!
app_mixmonitor.c: Unable to add ‘MixMonitor’ spy to channel ‘SIP/discador-00019868’