sql compare of 2 backups : index was outside the bounds of the array

gdubs

I'm on version 13 and on a trial. Currently trying to compare two backups and I'm getting this error (index was outside the bounds of the array). 

I can't seem to find a solution online for this error. Any recommendations?

gdubs

nvm, the error didn't show up if i restored db. so don't compare two backups, restore first then compare