no idea about issue for your specific tractor.
double check all bearings for all the pulleys / spindles are in good working order and no play / loosness.
double check everything set correctly as far as height and distance for pulleys for each blade, then pulley up on tractor.
double check to see if you have a "tensioner" something that keeps belt tight. sometimes springs go bad or the tensioner just freezes up / rusts up. to tight of a belt. and as the belt heats up from general use, it will begin to stretch. to loose of a belt and the belt "slides" around pulleys.
there are good cheap belts and then more expensive belts. it has been a while so i do not remember correct terms... i want to say a kevlar belt. has a higher heat resistance (more expensive belt) and can handle abuse longer.
do not use any sort of "belt gripper" or "belt wipe on / spray on stuff", for me all that stuff did was destroy belts extremely quickly. mower deck belts. generally rely on some slipping. and belts not aligning perfectly. between pully on tractor and deck itself. plus some twisting of the belt. that belt gripper / belt wipe on / spray on stuff. just eats stuff up quicker (causes more friction) and/or causes belt to slip more. either or causing belt to heat and break quicker. ((this is only my own small experience take it as you will))
over years on farm. every single finishing mower that touchs ground here. eventually sees tall weeds. and special care needs to be taken. to watch the spindles and make sure they are spinning and not stopped up from some large clog of weeds. for most decks, this means removing safety guards, so you can see top of the pulley / spindle going down to the finishing mower blades. ((rather dangerous more so if deck is on and foot slips down, you may end up loosing a foot)). my eyes tend to shift between keeping eye were i am going and on the pulleys / spindles. if i see one even begin to slow down or stop or like. it is "instant clutch" to stop tractor and turn deck off. and then lifting deck up and pulling the clump of crud out from mower deck.
with guards on. i would quickly burn up my belts. i do not always get a tall tell sound of a blade stopping, and belt heating up to point it starts to smoke) and need a good way to visually see things before belt ever gets close to smoking.