I have the same issue with several of my worlds - although not all of them. The notes and articles in the blue circle on the screenshot does not belong to the active world. This happens for all my worlds but one, which suffers another bug with its categories disappeared from the Athena and replaced with another world's categories (perhaps I should do a seperate bug report for that). I don't know if the two issues are somehow connected, but if you require more info please let me know.    

Hey there guys, your articles are not moved, the chances are your machine is keeping cache a bit harshly

You can reset the tree by using the 3 dots on the right handside of your world's name

Personally I didnt think categories are moving around worlds. I just said they displayed in the tree side panel categories from a world that is not active. The refresh from the three dots did nothing for me, neither did a hard refresh. As for the "continue working" list which is mentioned here what I said in my comment is that I have work from other worlds appear in the list of another- not that the work has been moved to a wrong world. Again hard refresh did nothing. I am sorry if I misunderstood what the bug report was about, but I thought we were talking for the same thing and since I got nowhere with bringing this up in development discussion channel in discord I thought to ask here