After installing a GFCI/AFCI breaker I turned on breakers individually and flipped breaker below new one and new one popped off.
Same thing on other leg - changed to new and breaker below it caused it to pop when turned on.
If I leave those lower breakers off and turn on new ones they stay on. As soon as I flip old ones on the new ones pop off.
I changed (CB3 20 amp appliance)with afci/gfci to have counter outlet gfci compliant. No room in outlet for gfci. CB 3 powers fridge and added dishwasher CB5 below it is also 20 amp breaker appliance powers stove, microwave, disposal switched at the other counter outlet. It has the switch for disposal and an outlet. House was built in 1977. I added the dishwasher and disposal. Dishwasher on CB3 and disposal on CB 5