I trashed 2 of the 4 segment cylinder drive belts last fall also. As well as breaking a brand new cylinder drive belt tightener j bolt after the original broke. I blamed it on slug feeding of green beans also and the fact that the belts seemed to be junk. Every time there was a belt issue the glued on backing on the 4 belts ripped partly off. There are little pieces glued crossway's to the 4 belts and then covered with a 1 piece backing. When the backing partly rips off you can't use the belt anymore because the idler needs to run smoothly on this backing and it can't do that with part of it ripped off and running rough on the glued on cross pieces  The J bolt breakage was unacceptable in my notion as it was obviously a manufacturing defect as it broke right where it was clamped/held to make the bend. BTW when the new one broke I had to make a 150 mile round trip to get a used one at a salvage yard since mother Deere saw fit to not stock a single one in the state of Ohio (thanks a lot for closing Columbus parts depot)  Now I know there are lots of 66-77-88 20 series machines still running in this area surely there ought to be one in stock. Had either of our little 1 store dealers been allowed to stay open they would have had 1 on hand because they knew what machines they had out there.

I'm considering going to 4 individual belts and doing away with the banded belt if the problem continues.

I'm putting in primary counter shaft and cylinder bearings as well as checking the variable speed pulleys for problems.