I don't have the colouring issue with ProRes, I think it's because I'm using 422 Proxy, but I've just discovered this problem.

The video shows first a ProRes converted clip, when I reverse it, it not only reverses it but also puts it upside down, the 2nd clip is the original h.264 and the reverse works as expected. This one actually made me giggle. 😁

I can't then rotate 180deg because then it's mirrored.