Cube 3D printer community

I have 2.08 firmware. I've used Cubify software on both Mac (mostly) and PC to create the .cube files.

I've printed probably 15 different files by now, from basic shapes to the highly complex and they all do exactly this same thing. I think I can rule out an error in the model.

I'm not sure I've ever used a stock 3DS .cube file. I will try this, though I don't think it will make any difference as no one else seems to have this issue even when downloading STLs from other sources and converting them to .cube format. 

Well at least I know now that it's not supposed to do this, so that's somewhat helpful in itself. It also makes me more determined to fix it! It's not the worst problem as usually the bottom layer isn't seen anyway and and excess can be trimmed, but of course it would be better without this blob.