Well, as you probably suspect, all prison phone calls are recorded, and there's usually ample warning that that is taking place.
I believe the best practice with prison calls to attorneys is to make arrangements beforehand that such calls a) are not recorded and b) don't take place "in public," ie common areas of the prison or jail, so there's no issue of invasion or waiver of privilege. That should be SOP both from the lawyer's standpoint and prison/jail operations.
AFAIK, the prison call recording system keeps a database of all the recordings that prison staff and prosecutors can call up and listen to any/all prisoner phone calls. The whole prison call thing is a bit scandalous, both as to privacy and cost, and also fairly sophisticated. A call with a lawyer should never be in that database.
So, I'd think a first level of blame would be with Luigi's lawyers for having a call over the standard call system. And to some degree with Luigi himself.
But, if you're conspiratorially minded, the prison/jail was recording calls it should not have and making those recordings available to prosecutors.