We have a number of triggers that either create or delete data from the various collections, however, we've started to encounter a problem and aren't sure why?
Your best bet is to try the same request with curl on the CLI first: "curl -sv %request url%" to see what errors are reported and resolve them there before looking at Matrix.
If there are no errors I think you can induce a similar error with SELinux, so it'd be worth checking that's in either disabled or permissive.