Kwikset 914 being excluded without my asking

I have successfully included a KwikSet 914 lock and everything works. Then I go to exclude a different device - I activate exclusion mode on the Z-Wave controller, I trigger exclusion on a different device - and my KwikSet 914 suddenly gets excluded and now all I can do is delete it and start over. This has happened to me twice. Note it does not get excluded without my asking every time I try to exclude something else.

Is something somehow pressing button ‘a’ on the lock?

I don’t think so - the cover is on and everything is secure.

I mention it because pressing the button is needed for inclusion & exclusion.
Have you ruled out the possibility of weak batteries in the lock?