Without researching in depth, I did poke around a little & need to toss out some ideas.
My guess is that the wrong reply actions are getting associated with your folders. I think it would help to create a new folder and confirm that the problem exists, (switch to it)
Then start removing folder actions. Which one of the actions needed to be removed to eliminate the problem? (I'd start with the replys)
Another thought: is your ($inbox) signed by OpenNTF Template Development on March 28th?
Dwight Wilbanks