Hello,
Former Anaplan Support member here. I was just about to create a Support Ticket for this intermittent error message, I wanted to see if there were others who have run into this message before?
1) I am checking to see if other users are facing this issue.
2) This is not model or workspace specific. I have already tried clearing my browser cache/cookies. I have tried both Chrome and Firefox. I am also on a Windows laptop. This gives me an indication that perhaps the issue is not User specific.
3) This issue is not chronic, but I would say I run into this numerous times a day at random points and I have not noticed a pattern or trend as to when it occurs. This usually happens after I perform some kind of browser navigation (ie; clicking or opening a module, list, saving a formula, creating a line item etc) in other words I do not see this error message when I am not actively doing something.
4) The issue does not seem to impact the changes I am making, it just pops up and forces me to press ok. Then when I do the page refreshes. Thankfully I don't lose any progress but it is annoying to have to deal with this from time to time.
5) This seems to be more frequent over the past couple months or so maybe? I never encountered this issue before, so I am beginning to wonder if it is tied to one of the recent releases?

Look forward to hearing from the Community on this.
Thanks,
Daanish