Doesn't seem to matter what view I am placing text in, clicking the Close button pops up the warning. I'm curious if others are seeing this too? I was using the stock architectural template from the Imperial Library. Simple fix is to just finish text in the same old way, don't use the Close button.
Edit: A little more testing and the plan view Level 1 doesn't seem to mind anymore. When I tried it again in the Construction template the floor plan view Level 1 didn't complain but Level 2's did and the Ceiling plan for Level 1 did too. Okay...more weirdness. This is after placing text in an Elevation view.
Traded emails with Aaron Maller last evening and pinned down the circumstances that this issue is reproduceable. It boils down to placing text in a view and then placing text in another view while the previous view is still open. Revit doesn't seem to recognize that the new text is in a different view when the Close button is used. Here's a video explanation.