I've noticed that when I use Crop or Offset in my input strips to select parts of the input image, these values will be misinterpreted if if I use Proxy differetn than 100% in the preview window.
This works as expected for image strips, but breaks when using movie strips instead.
Looks like the Crop and Offset is applied without compensating for the altered proxy footage dimensions. They should be compensated for the proxy size.
My use case:
I capture a single 2*1920 x 1080 resolution footage to the split it into two FullHD moving images. It's hard to edit this without using proxy and I can't use proxy because it breaks my image splitting using Crop / Offset so I'm doing my editing with 2 seconds per frame performance for now.