So was trying to figure out why Trump waived privilege here. Here's the most likely scenario I could come up with. The special master had determined the recording was privileged. Cohen's team likely didn't concur on that (there are other people ("privilege breakers") present on the tape and the crime/fraud exception could potentially apply) and they were dead set on releasing it given the bad blood between Trump and Cohen. Trump is informed of this. If he wants to prevent disclosure, he would need to seek injunctive relief (i.e., a court ordering Cohen to restrain from releasing the tape). But he knows that this will probably get out at some point anyway. So seeking injunctive relief would just make it look like there is something really bad in the tape that he does not want out there. So instead of seeking a TRO or something similar, he tries to get ahead of the story by having RG say that they're not asserting the privilege and spin it as exonerating him. In short, RG had a bad hand to play and tried to do the best he could.