I would not be surprised if this chain/unchain system is also one of the invisible reasons why some people have found the combat in BG3 too challenging (which I honestly don't think it is, but I've seen the complaints).

The terrible movement management encourages you to simply move your party forward as a group into encounters in the most vulnerable formation, as opposed to splitting up and scouting ahead, etc. Of course every fight will seem unfair when you start them surrounded and pounded.