I’m pretty sure PECOTA had the Cubs’ defense as a negative when first published last year, and they changed it once someone pointed it out. They have the Cubs at least two wins (and probably three) below where they should be because of their defensive projection.
I think most defensive metrics had Contreras above average last year because his throwing/athleticism is so good that it outweighs his receiving negatives. If they have him below average, I think they’re wrong.