Even on a work stand, he could hit the button when installing the bike on/taking it off the stand.
After reading this thread, I checked my bike because I've had this issue occasionally. Sure enough, the limit screw was just a bit too tight, and I could semi reliably make the shifting go up to the largest cog but not "give up trying", as if it thought it wasn't fully there yet.
Only time will tell if this fixed it, but after seeing the behavior, I'm pretty sure it will.