Maybe, maybe not. I don't know if this kind of thing reaches trial at any point, but I wonder if discovery would turn up any sort of direct code copying or reverse engineering done by poached employees.

Perhaps the company even used decompiled code, it's not out of the realm of possibility that they simply directly stole the whole thing.

I'm not sure any of that is actually likely, but I think that the fact that some paragraphs are directly lifted is a massive red flag.