So today I wanted to check in on one of our sub's local trolls that I haven't seen post or comment in a while, and their entire history appears deleted. There is no history at all. Opening in incognito & not logged in reveals the history is still there.

This is consistent with being blocked, except according to Reddit help,

Blocked moderators can still see, reply to, and take action on posts and comments redditors who have blocked them make in the moderators’ communities. Blocked moderators can also access the profile of someone who’s blocked them to see the person’s history in the communities they moderate (but not their full history in other communities).

The user has plenty of history in the sub I moderate - I was able to view their comments in the sub, but when I navigate to their user profile, their history appears deleted, including currently active content in the subs I moderate.

I can see the user's history by opening their account in incognito. However the site should work as described in the help.

It's a serious issue if a user can stealth their behavior from mods in this manner.

Please advise.