I wonder if you have any of these settings set for your Support category (in particular the “default categories regular”) [Normal used to be called Regular.. this seems a hangover in the settings language]
I think I have found the reason for my issue - which is in a PM group… this has a similar setting [NB have changed the text to Normal Automatically from just “Normal”]…
Now that I have set it to “Normal” the message topics seem to be setting to this automatically no matter what the user has the group notification setting set to themselves (which is unexpected! I thought this was just the default INITIAL setting which people could override) - it was previously on “Watching” so it didn’t matter what people had it set to themselves then either, it set the messages to “Watching” [as a possibly separate/related bug, the group notification setting changes people make are not saving…]
Copying @JammyDodger 