Incorrect RGBA resampling in Warp plug-in
Submitted by Raphaël Quinet
If two pixels have different opacity values (alpha channel), then their colors are not averaged correctly by the Map->Warp plug-in. It looks like the RGB channels are resampled without taking the opacity into account. As a result, the (invisible) color of a transparent pixel can bleed into an opaque pixel. The resulting image is incorrect.
See bug #70335 for some test images and a longer description of the problem. This problem affects many other tools and plug-ins.