I opened the same files in the classic Pixelmator, and there they look like what they're supposed to. I used the classic Pixelmator to "convert" the .psd files to .pxm and I opened them in Pixelmator Pro, and then they looked like the original files I received.
The screenshot I've attached shows the difference on how one of the .psd files look like in Pixelmator Pro (on the left) vs how it looks like in classic Pixelmator
