Secondary rollers and high vs low

Hello,
Just got my 900 Trail back from dealer for propshaft carrier bearing. Took it for a blast and noticed belt slipping under hard acceration!!
WTF i am thinking, pulled the cover and discovered big flat spots on my secondary rollers (the ones you can see with it installed).
Read up a lil bit on here and watched Todd’s video on his site.
Went and bought new rollers from dealer ( sorry todd, had a ride to do the next day).
Easy job to do, my inners were good. You dont have to disassemble the whole thing for the outers, just remove the helix.
That all made me think of why this happened at all. I usually always in high. Got used to that doing 8K on my 08. I am now running low for any riding below 25 ish. I am not an expert but we will see if this helps.
Any thoughts on this or similar experiences??
Thanks.