If the current frame was not in range, the ImageTile's 'ok' was stuck at 0. Similar to the ImageUser being reset to 'ok' in BKE_image_user_frame_calc, we now do for ImageTiles as well. note: the crasher part of T74225 was fixed in rB5c490d437743. Maniphest Tasks: T74225 Differential Revision: https://developer.blender.org/D6939