Okay checked in both Stable and Tests passed.
Stable only has Replace no separate link setting in Watched Words.
With or without regular expression turned on the replace watched words doesn’t work with the /bword/b. In fact you need to add the /bword/b for word to be recognized instead of just word
Test Passed works without needing the /bword/b in Link watched words.
So looks like just need to wait for Tests Passed to roll out to Stable.