Hi Everyone--
The New Text team has recently noticed this also. Oddly, it's not an issue with New Text (or text at all)... instead, there is a bizarre glitch that will very occasionally (and seemingly randomly) cause a view to be interpreted by Revit as being mirrored. We can get this to happen most often when opening a view containing a stair while slightly zooming with the mouse wheel. As you've noticed, the next time you close and open the view, everying will very likely be fine.
When this mirroring happens, the most user-visible issue is the text editor--which is pretty much working correctly in the bizarro-world mirrored view. So, we're working on correcting this weirdness very soon!
Thanks for your vigilance!
Trey
TreyKlein
Principal Revit QA Analyst