2.7 TDV6 timing belt damaged on front edge

[twr7cx]

Doing the timing belt on our (new to us) MY12 D4 TDV6 with the 2.7 engine. Just accessed the front and found that there is damage along the forward/front edge of the timing belt:

https://i.ibb.co/0CxpwZN/IMG-4316.jpg (https://ibb.co/0CxpwZN)
https://i.ibb.co/mqGpjmf/IMG-4315.jpg (https://ibb.co/mqGpjmf)
https://i.ibb.co/0KGMKrP/IMG-4319.jpg (https://ibb.co/0KGMKrP)


Looks like a lot of the belts rubber mess has gone into the idler pulleys:

https://i.ibb.co/QMR6yMt/IMG-4318.jpg (https://ibb.co/QMR6yMt)
https://i.ibb.co/s9QSrFz/IMG-4317.jpg (https://ibb.co/s9QSrFz)


The belt seems to be running hard agains the front edge of all the pulleys with some lip overhang on the idler pulley and belt tensioner pulley:

https://i.ibb.co/54x80c0/IMG-4320.jpg (https://ibb.co/54x80c0)
https://i.ibb.co/j3wmS99/IMG-4321.jpg (https://ibb.co/j3wmS99)


I'm replacing the belt, both idler pulleys and tensioner - any special considerations to avoid this or anything else to check regarding cause of?

[Eric SDV6SE]

Check the toothed pulleys for axial play and replace if there is any. Seems like the belt has "walked" towards the front edge, maybe never installed correctly. Good pick up.

[twr7cx]

Check the toothed pulleys for axial play and replace if there is any.

Have pushed and pulled and tried to wriggle them as hard as I can. No movement.

[twr7cx]

I've installed the new belt centrally on all the pulleys and cogs. Have pulled it through two full crank rotations and it seems to be tracking well.