Yeah for the artist too it will be way harder for them to find future work if they got fired for plagiarism. No big company will want to deal with you if you got fired for that. Hell I even play it super safe in my old design/production job when I had to deal with customer artwork and logos. If anything looks like they ripped someone off, I immediately bring it up since I rather not support stolen work and I don't want to be associated with it. Most of the time too they don't even see the files because the file type is something they need a specific software to open. They assume we have the knowledge to know if its breaking copyright or not.

In the case here, it could be similar but legal finding out this is a copy of something else might also be a bit difficult. The stuff I found that might have broken or did break copyright was usually breaking it from an obvious known company (like Adidas or a sports team) but this one I don't think is a popular known art work so it would be harder to find out about. Plus it is weird to just assume your artist is going to blatantly copy someone else's work like this. Literally would be ruining your own career doing this.

I will say though I think this was the second time I heard something like this happen with Activision so maybe in this case they should either get their legal team to check everything regardless though it will be a bit challenging or they need to heavily work on their application process for their artists. I do wonder though if crunch time is a huge thing for these artists like maybe they barely get enough time so out of pressure they just find something online and try to alter it a bit to try to hide that it is someone else's work but also just assume its enough editing that it isn't considered stolen work. Last point is still bad but I feel their handling of content like this is super strange.