Relationship trait bug - wrong traits showing in my spouse's description!
On the sim you didn't change the game will show the traits that sim knew about the one you changed last they talked about the traits. On the one you didn't change, you have to do "get to know" socials on the one you changed to update the panel information. You may have to do this multiple times to update all the traits they know about the other sim.
In regards to their behaviour it may take several sim days before they start to behave according to the new traits, just because of how the game works - it's almost like they have to shake off their old behaviour.
I've never used 'Change sim' because I find it easier to just cheat and edit sims in CAS, but the above works for every sim where I've changed traits. As such I can't speak to whether 'Change sim' is bugged or not, but it wouldn't surprise me if it is.
