Mower deck 2206 - Frequent PTO Belt breaking

I've had a problem free mower and proactively changed the PTO belt with a OEM 754-3068 this Spring. The new(er) PTO belt recently and suddenly frayed while mowing. I installed a second new OEM belt and it lasted 15 minutes before the belt broke cleanly.

I've removed my deck and inspected and see no smoking guns; All pulley bearings are tight, Clutch appears in good condition, springs okay, etc. I'm at a loss for how I've broken two PTO belts in under 20 minutes of operation.

The only thing odd/off is my Spindle Belt (7564-3041) is contacting the deck plate assembly mount every so slightly on the SAE right side (pass. side). Any thoughts, or ideas? Thanks a bunch!

That deck is getting a touch on the old side , how are the spindle bearings ?
Also the pivot bushing on the tensioning arm, should have been replaced at least once by now.
Because the deck is spun by the double pulley, any excess load on the blade will also put an excess load on the PTO belt.
Double check the bolts that hold the deck lift & tensioning arms onto the deck, they can get loose & the plate fretts & splits.
Occasionally I have needed to reweld the two hanger mounts onto the plate as they crack along the weld.