I've seen some info online regarding this, but none of the solutions have helped. Using Office Professional 2021 (installed from disk). Starting today, while Ctrl-i and Ctrl-u work fine toggling the state of a single word, Ctrl-b toggles the entire document (and back on second press). Style is Normal. Happens regardless of font.
Done the following:
Local repair of Office
Recovering archived copy of Normal.dotm from before


Ran Word in Safe mode -- problem did NOT manifest!!
Since Style=Normal, there's no issue regarding whether "Automatically update" is checked or not
Looked in Com Add-ins -- nothing identified as "active or not"
HELP?