International 9400 6NZ ac belt issues

So I have a international 9400 with a cat 6NZ c15 2002 model year. I’m having issues with the ac belt and only the ac belt breaking. For context this truck has two belts a 6 rib and 8 rib. Into the story, last year we replaced the ac compressor twice the original then an after market which locked up. So we replaced it again with another aftermarket compressor, this one is still on the truck ac works perfect. But we keep breaking belts to the point of 15 in a year. The compressor and fan pulley have been straight edged so they are in line the compressor is where it’s supposed to be there’s nothing on the pulleys that’s cutting it. Other then manufacturers defects on the belt what could be the problem?
also the idler has been replaced, the tensioner is a rod with two bolts that doesn’t seem to be the issue the tensioner is part of the compressor mount I believe

TL;DR
I have broken 15 ac belts with no obvious problems, new compressor, new idler.

 

We have tried tight and loose and everywhere in between this most recent one was too loose.

 

Yes as far as I know the compressor is square to the block

 

You could be on to something here. Our problem is we aren’t really sure how much it’s supposed to have. The ac is coming out the vents at 53-55 degrees, I’m the driver I’ll ask my boss what he thinks.