The sponsors are also bugged for me on PS5.
All sponsors that have been completed by me prior to the update show a completion of "3/3", but the two first tasks of each of these sponsors are not checked and show kind of weird values (I'm trying to provide screenshots later or tomorrow).
Another problem with sponsors is that I need to complete all three tasks of a sponsor in one session (which means: not leaving the game or turning the console off) and then change the sponsor to another one, so that the progress I made in this session for the specific sponsor is saved after leaving the game.
Otherwise, the first two tasks bug out after reloading the save, show strange values and, more frustrating, are not counted to the overall progress of the sponsor anymore.
PS: I hope you're understanding what I'm trying to say. English isn't my first language. 😅
Edit: I sent in a bug report. Feel free to add additional information if you have any. :-)