This is not allowed glitch

For some reason whenever I post things it randomly says that message can someone please explain

This happens when your message contains something that triggers the bad language/forbidden filter or whatever it's called.

There might be other causes I'm not aware of.

Yeah, it's content being filtered. It used to pop up a red banner instead

But why is this happening in private club too, I thought chess.com was more lax on clubs

They usually don't do active moderation on clubs, but the filter applies everywhere.

Yes but this wasn’t the case before which means the filter isn’t working properly because clubs have been exempt from filters prior to this

I don't think clubs have been exempt from filters. They're just not moderated by human moderators.