Sims won't workout in fitness attire

Hello, For months now, my selected Sims and NPCs are not changing into fitness attire when they go to the gym. I am able to change outfits manually, but the NPCs are working out in everyday clothes. Looking for advice, please. Thank you! 

Edit: If I use the debug cheat Reset Object on the equipment (or pool) the Sim is using, they will get kicked off and changed into the proper attire. Now that I've done this and saved, it seems to have fixed the issue but will continue to monitor.