I experienced this as well. Notably, after installing a mod that increases the traits limit. Because of how traits work, lot traits and werewolf temperaments seem to be affected as well. Do you have such a mod installed? If so, try uninstalling the mod, then disabling script mods. The last part is important, because if the mod is just uninstalled, the behavior will continue unless you essentially reboot/clean the running mod scripts by disabling, loading into the game, saving and exiting, and reenabling them. Next time you load up your save, this issue should be resolved. This worked for me, at least.
Note: You will need to go through and remove the additional temperaments on each werewolf after doing this.
