Some webhooks seem to trigger periodically without user action

Hello,

I’ve recently discovered and started testing the Discourse webhook feature (I’m working to add support for it to the rbot IRC bot). I’ve enabled a webhook that triggers in all events, and one thing I’ve noticed is that even with no forum action I’m seeing periodic updates to the built-in groups (admin, moderators, staff, trust_level_*, everyone) and users (-1, -2) being added to groups. I also periodically get notified about updates to categories, even if nothing was changed (manually). In case it matters, the Discourse instance is the GPUSPH one, graciously hosted by Discourse itself.

I was wondering

  1. why these events get triggered (they seem to be always the same) and
  2. is there maybe a way to filter out these events specifically (leaving the same event classes active)?

(Sorry for the early post, misclick)