I've been following this site for a while now (anonymously) and now have an issue that I think you kind folks may be able to help on! I have searched the available responses and have found nothing that specifically answers my needs. Sorry if this is somehow a duplicate.

I have a circuit in my home that all of a sudden started tripping. The house is about 10 years old and using modern AFCI breakers for required spaces.
It's a 2nd floor arc fault circuit, with (1) duplex outlet and (1) closet light switch on the master and (3) duplex outlets with a switch to a hot outlet and a ceiling fan/light combo in the other bedroom.

The circuit was working in the morning, when I used my closet light and my daughter used her bedroom lights. But around 2pm I went to the closet again and the lights didn't turn on. I figured bulb burned out but then when I saw it was 2 bulbs I thought something else was up.
I went to check the breaker and the afci breaker was tripped. I tried to shut off and back on again, but it was already "off" and when i pushed it "on" again it immediately pushed back off. I swapped that AFCI outlet for a standard (same wattage) breaker, and when i tried to turn it on it sparked and hummed for a second then shut back off. So, thoughts is it's not the breaker that's faulty...

I am slightly familiar with electrical, so I started testing.

I swapped out the breaker and it worked just the same, so it doesn't look like a breaker problem.

I did a continuity test using a multi-meter on everything i could find on the circuit and everything sounded good - good connection -- including switches, outlets, and fixtures.

I can't find anything wrong. What is going on? If you have questions, please ask. I tried to cover all the bases (like "are the grounds connected?") before asking the community, but then again i'm no pro like some of you folks!!!

If nothing else, it's feeding my daughter's room so I need to feed her gadgets or i'll loose my mind!!!

Thanks!