Polo's attorney Bradford Cohen tells TMZ this is something he's never experienced in his decades of work ... law enforcement releasing what he calls "heavily redacted" body cam footage, and only "the parts that disparage the defendant."

Cohen says there are crucial moments in his arrest that were left out of the released video -- "They didn't show him getting slammed to the ground or the reason why was pulled over. Of course, they wouldn't show that."

The video does show Polo verbally berating one of the arresting officers, but Cohen says that is "part of being a police officer out in public, people are going to say things you are not going to like."

He thinks Miami PD was embarrassed because it had no probable cause to stop him or arrest him last June, and the case has been largely dismissed after Polo completed anger management classes.

Here's the wild card, though -- we asked Miami PD why it only released portions of the arrest, and a spokesman told us the department did NOT release the footage ... which first popped up Thursday on Twitter.