I have a 4 month-old house with a 200A Square D Homeline panel. There are AFCIs on some circuits, and others are AFCI/GFCI. I am having NO problem with the AFCI breakers. But here in the last several weeks, three of the AFCI/GFCI breakers in the panel have started tripping intermittently, usually with no load on them. One AFCI/GFCI serves a single dedicated 20A laundry room outlet, another is to the master bathroom, and the third one serves 2 - 20A outlets in the kitchen. Interestingly, these three breakers are connected to the same busbar in the panel at slots #12, #14, and #18. The AFCI/GFCI breakers on the other busbar have no problem. The three breakers all trip simultaneously. I can reset them, then they can be just fine for a couple of days or a couple of hours before they trip again. This doesn't seem to be related to connected loads. I can run tools and kitchen appliances without problems until some unknown event kicks all three breakers off. Could this be a problem on the power company's side of the electrical service? Any and all advice appreciated!!
The part where you said they all trip simultaneously and the fact they're all back-to-back makes me suspect of a bad buss bar. Other than that there should not be any correlation between any of these isolated circuits. It's plausible, but highly unlikely the manufacturer shipped out a bad case of breakers and the installer just happened to install them back-to-back but realistically not heard of. Just replace or as Trevor mentioned in his comment swap the known good AFCI with known bad ones and check buss bar for burnt marks. See what happens.
AFCI's are a tricky beast, and I had a similar issue with My house (purchased new in 2011). I ended up having to replace both of the offending AFCI's, and have since not had any issues.
This might not be super helpful, and would be expensive to buy 3 to test, but my electrician spent alot of time and money (mine) to determine that my circuits were fine and my breakers (purchased at the same time) must be experiencing a similar manufacturing defect.
I had the same problem recently. The problem turned out to be a solar system hooked to the same power transformer completely different service and building. You need to look for what is making the noise in that leg of the power it can be the range dryer or even from another service look something new that has recently been hooked to transformer good luck let us know.