It's a tough call whether that's a bug. On the one hand, the forming press shouldn't require extra materials that aren't required by the inscriber press (e.g. the polyethylene used for making an empty circuit board). On the other hand, making the other circuits in the forming press requires extra pre-processing compared to the inscriber press (e.g. gold plate instead of gold ingot, diamond plate instead of diamond gem), so applying that to printed silicon makes it more consistent than before.
On a slight tangent, what gives you the idea that the AE2 inscriber press is "bloody slow"? In my survival game, without any acceleration cards, it only took just over 5 seconds per process, which is on par with the MV-tier GT forming press for circuits and printed silicon. For making the processors, an LV assembler would be slightly faster, so you might have a point for that part.