My sim changes into her career outfit before she leaves for work every day, and every day when she leaves work, she's in her everyday outfit. I've taken out every single piece of CC and every single mod that isn't NRaas, and it's still happening. Is it an NRaas setting that I messed up? Or is this just a weird glitch? It happens in every world I play in, and I don't remember when it started.

This is a function of StoryProgression (SP Career module required).

NRaas > SP > General Options > Options:Careers > Change Work Clothes
NRaas > SP > General Options > Options: Careers > Force Change Work Clothes

The first setting uses trait scoring to determine which sims, if any, change clothes upon finishing their workday. The second one forces the change on all sims regardless of trait scoring.

Thank you!