@Cernel The problem happens when a combat is started, after single clicking a new combat. The delay between last combat and new combat is normal, a second or so. There is no double clicking. Units with "canEvade" property are slightly suspect, but it's not clear what is causing the issue.
@RogerCooper FWIW, I think you should be able to click the 'X' button to close the blank combat prompt and TripleA will become unstuck. If you hit the issue further, save games and noting which battle caused the problem will be of help. If anything with more data, we can start looking for common patterns and see if we can eliminate any potential possibilities.