The dead key never worked right after startup (but kicked in after half an hour).
I discussed this with Ron last March.
At the time it seemed possibly related to voice recognition. Perhaps in connection with VoiceComputer. Ron and I chewed this over here in this forum, but the conclusion was that this problem had nothing to do with VC.
I recently stumbled onto a “fix” for the mysterious dead key lag here:
This collection is huge, but the one that helped me is
It located a broken link. I deleted it, and now the dead key works rock steady from startup.
The rogue link had nothing directly to do with VC, Dragon, Word or any of the usual suspects. It was a long-forgotten link I hardly ever use, but Win10 always found it at startup, and it took the system 20-30 min. to deal with it.
I hope sharing the above link to batch scripts will benefit others here.