So I dropped a bunch of AI files into Photoshop the other day and was exporting them when I noticed one of the layer names didn’t match the file name. I never rename my layers since I delete them after.
It may have applied the same numbering across the layers if you dropped them all in at once.
I did drop them all in at the same but it didn’t rename any but the that one. It was a super weird glitch I haven’t ever seen again.