This would happen if a tile is found on disk, painting would actually request that tile (because corresponding uvs were in that range), but that tile was not added in blenders list of tiles in that Image. Need to also check tile in `image_quick_test` (regardless of iuser having passed). thx @lukasstockner97 for additional input! Maniphest Tasks: T73110 Differential Revision: https://developer.blender.org/D6578