Rug sitting oddly

[Rusky]

Put rug on my horse only to find it seems to be scrunching up a bit in the saddle area of his back.he hasn't lost weight, can't think what else it can be. It's same rug he wore last year.

 

[Barton Bounty]

Put rug on my horse only to find it seems to be scrunching up a bit in the saddle area of his back.he hasn't lost weight, can't think what else it can be. It's same rug he wore last year.

Sometimes it can bunch up due to shrinkage with the rug drying from wet