According to Armando Salguero of the Miami Herald, the Dolphins knew. And they didn’t disclose anything about Bess while trying to trade him.
From a short-term strategic perspective, the decision to remain silent made sense. Buy low, sell high, buyer beware. But as Salguero points out, fleecing another team via trade makes it harder to do business in the future, since other teams will find it harder to trust the Dolphins.
Ideally, the Browns would have known about Bess. Even more ideally, the Dolphins would have acknowledged that Bess had an off-field issue that needed to be fully investigated before flipping fourth-round picks with Miami, sending a fifth-round and seventh-round pick to the Dolphins, and committing to paying Bess a fully-guaranteed base salary of $2.683 million in 2013 and $3.067 million in 2014 as part of a three-year extension done after the trade. (There’s a de-escalator for 2014, but it’s unclear what causes the salary to drop, and by how much.)
So while the Browns may merit some blame for not knowing about Bess, the Dolphins deserve criticism, too, for not being honest about the situation. Even though G.M. Jeff Ireland is now gone (and the Bess mess could make it harder for him to get a new job), others in the front office who knew or should have known about Bess surely remain, which will make other teams leery about working out trades with the Dolphins even after a new G.M. is hired.