The switch that suddenly reversed itself is a single switch thats on a different circuit from the one that wont turn off. There are no on or off markings but the light that stays constantly on is controlled by one switch that is located on panel with 2 other switches.

How To Wire A 3 Way Switch Wiring Diagram Dengarden
Light switch reversed itself. With large switches it is considered should anything drop on the switch and operate it then it should switch it off. The other 2 switches appear to either do nothing or they are dead. Maybe worth pointing out that if you plan to change a light switch you pay very careful attention to where the various wires go and ensure you put each wire in the same terminal on the new switch. Hj mar 22 2011. If it is a single pole and not a decora style it should have on and off printed on it and would be impossible to reverse the function. Look at the switch.
A corroded contactor inside the switch could cause the flicker but would also probably cause the switch to feel warm at the touch. The other 2 switches appear to either do nothing or they are dead. The switch that suddenly reversed itself is a single switch thats on a different circuit from the one that wont turn off. Ive had switches where they kinda seemed to have reversed but once you fuck with them for a minute everything lines back up to how its supposed to be. But you are describing a three way switch and the other one was used to turn the light on or off which reversed the function of the one you usually use. With non two way then must turn switch.
Went to home depot and bought new dimmer boucht cfl compatible dimmer as tried cfl floods before and they only lasted a few weeks hooked up same way as before. A wire getting loose in a terminal screw or in a wire connector at the switch or light fixture could cause the flicker. Either switch can turn the light on or off. If this is the case perhaps the other switch is seldom used and. Took picture and my wife double checked 3 black wires on top right. Dimmer in kitchen 5 dimmable flood lights went out.
Another possibility is that someone literally flipped your switch. With the switch mounted in the upright position. Id recommend getting it replaced. The switch and dimmer work fine but the operation of the switch is reversed. Third it is a three way switch. Moving the switch lever to the up position turns the lights off moving the switch lever to the down position turns the lights on.
This can be caused by different events. If a two way switch swapping l1 and l2 assuming one terminal marked common will swap the way they work. There are no on or off markings but the light that stays constantly on is controlled by one switch that is located on panel with 2 other switches. However what is the right way. That means there are two switches controlling one light. Loose electrical connections can lead to fires.