Is it ok for management staff to discuss any informaiton with other employees during an investigation they are doing on another

It completely depends on the type of information they gave out. For example, if they disclosed that you had a disease and it had nothing to do with the investigation, that is one thing, but if they said, we are investigating whether there was a sexual harassment of Jane by Joe, then that would be okay.

My standard disclaimer: I am not offering legal advice, assume I do
not know the law in your state or at all for that matter and that I am
just making suggestions for starting points for when you do speak with
an attorney. Do NOT rely on anything I write and contact a lawyer in
your area immediately after reading my posting.