I'm using the latest version of CSP (0.1.38) and SOL but I have tried 1.36 & 1.37 just to make sure its not CSP messing things up but I get the same issue.Yeah thats definitely not normal, I wish I had any idea how this is happening and how to stop it, I've never seen anything like it. Looks to be displaying the Ext_decals texture over the top.
I'd suggest trying to delete the files and reinstall the mod, though it seems you installed it correctly considering the car boots. Are you running stock vanilla AC, no CSP mod or anything?
I have also tried to install with CM and normally but nothing seems to works.
Considering I know nothing about modding and it might be a terrible idea but what if I try to remove Ext_decals?