Ceiling Light acting odd when interacted with from two switches
It sounds like you have an old school 3 way dimmer switch, the dimmer only works when that switch is in the loop. Newer electronic switches don’t have this problem I like the lutron maestro these work together so the dimming works at both locations , they also have a 10 second fade to black that gives time to cross a room. They are expensive but will solve your problem , this or replace the 3way dimmer with a standard 3 way switch.