I haven't seen it posted yet, so here's what's supposed to happen when the lounge is closed (and the lounge breakfast can't be provided because of that):
https://members.marriott.com/wp-content/uploads/2018/05/MAKHAR18008_TBOP_Microsite_Platinum-Elite_Lounge-Access_Final.pdf
Basically it says: breakfast in restaurant for guest +1 or 750 points per day.