Update 11/1:
Happy to say the issue hasn't returned. More food for thought: I also somewhat recently went from 3x5 to 3x3 on the bench press, so perhaps the higher volume at the heavy weight was causing issues. As a matter of fact, since the last update, my thought is changing to 3x3 may have been the top solution. The last couple bench workouts I haven't paid as much attention to the cues mentioned in the last update, yet I haven't had any returning aching issues. Just a guess. Who knows for sure.