PU has had this problem for a while since one of the very prominent and better Pokemon, Machoke, often uses the move Dynamicpunch. The move itself isn't the only option Machoke has for a STAB (since Close Combat + Guts has a niche) but it is by far the most used option and it is because of the nasty confusion side effect.
Dynamicpunch has been around for a long while as we all know and when we asked SS almost a year ago about getting the chance to suspect it, and we weren't allowed to do that.
Partially because we were still looking for official recognition and didn't want to stir up drama and partially because Policy Review wasn't as active that time the issue kind of dropped out and remained in the back of our heads.
The PU council already agrees on the fact that Dynamicpunch on Machoke is obviously an uncompetitive move akin to Swagger (and Chatter on Chatot which is banned) since it directly affects the outcome of games but on everything else
The ban in itself wouldn't nerf Machoke sets that need a STAB move that doesn't drop Defenses since Cross Chop would be a fine alternative on No Guard movesets.