Corona ignores Region rendering

Hey,

just after updating to corona 4, Corona starts to ignore an render Region (in the Corona VFB)

any ideas?

(it starts rendering, but the whole picture, not the selected region)

Just to check, do you mean the scene is loaded with Corona 4 installed without a render region, and a new render region is drawn, and IR or final render is started, and the region is ignored? (Rather than, say, the scene is loaded with a region created in Corona 3 already saved with the scene)