I'm not sure about workout clothes. For Sara it was her work clothes, the mixology outfit since she owns the bar. But it's mostly every day outfits (like Agnes and Agatha's) and then the cold weather for the day everyone froze to death. I JUST opened the bar and this is what I came into: an unknown NPC and Sara Scott again (working her bar) in just their underwear. Screenshot is attached.
It's happening with all the outfits. I was playing my own Sim in her every day outfit. I swapped households for a minute and as soon as it loaded, my Sim, who was on the same lot, was in her underwear. It's really weird but it's happening a lot more frequently now.
