Hey, this is an old post and I hope you haven't given up your KY license since then but I can add two things just incase people have this issue in the future.
I work with Siemens panels pretty much elusively and have worked with Siemens tech support on this issue.
I have had an issue where a newly rewired house still didn't have the final connections made to a peninsula receptacle and it kept tripping the breaker. After the final connection was made, it stopped.
I have had an issue with an insinkerator (super heated water dispenser at the sink) that would trip the breaker. It would take about 1 hr or so and then trip it. Talking with tech support they said to plug this surge suppressor into the outlet and then plug the insinkerator into it:
This helped in that it increased the time that the circuit stayed untripped. It lasted maybe 12 hours and then tripped. (pretty fascinating to me, because the time delay would indicate to me that it is related to a cycle in the sinkerator and that is why without the surge suppressor it would trip when maybe the heater turns on? I don't know but in that 12 hr time frame it should have gone through the cycles multiple times).
In the end, that wasn't a plausible solution. Had to change the breaker.
The reason why they say to replace the breaker with new ones is that if for some reason you got a "new" one but in actuality it was a "new" one but just never used or opened but it is from stock that was around from last year that breaker may not have the latest firmware. Siemens constantly tries to update their algorithm for detecting the arcs and that is why it is important to get the latest version.
Siemens also has a tool where you can test AFCI circuits. It is expensive though.
Also keep in mind that the AFCI requires a min load of 5A (i think that was the number) before it starts sensing for Arcs.