I'm not closely following it so this might not be accurate, but I read this today that the issue is not the new hit rule but some clause the Bears (and other teams) are putting in rookie contracts allowing them to void deals if they do something "detrimental to the team" https://www.windycitygridiron.com/2018/7/30/17630438/report-chicago-bears-roquan-smith-contract-hold-up-bonus-language-restriction-agents-nfl-players