Strange electrical/Breaker issue (solar related??)

I would guess your breakers are tripping at below their rated current, and it is an issue with low quality thermal breakers. This would also explain two apparently unrelated faults, if they are using the same breakers. I can't see from the photo, but is there a manufacturer and part number on the breaker? Not to be rude, but based on the photo of the installation, this does not appear to have been done by a careful professional.