Are you using a 2 pole AFCI breaker?AFCI breakers will trip with loose connects, ground and neutral touching. Why do do they trip using a 3 wire shared circuit, like a GFI?
Are you using a 2 pole AFCI breaker?
I believe a 2 pole AFCI breaker will solve your problem because you will not have to create a 3 way splice in the panel for the 3 wire neutral to be connected to both single pole AFCI's.
What I think is the 2 single pole breakers are reading the neutral current and it's not matching the current draw in your ungrounded conductors.
Not sure what you mean, you have to use opposite phases on a 2 wire shared neutral circuit.
That's correct, and the neutral would have the difference, 3 amps on it.Let's say you've got 5 amps drawing on one breaker and 2 amps on the other, the current on the neutral will not be the same , because the neutral I carrying the current from both circuits and will not match on either breaker the unbalance should trip the breakers just like they would if they were GFCI breakers.