Hi,
According to the original hardware Ensoniq SQ-80 manual, then the LFO SQUARE waveform is positive going only. So it seems to be correct Arturias do likewise.
I think the Graphic display should show this behavior though. The MOD MIXER does show the correct positive cycle.
If you use the MOD MIX and in example choose any waveform except SQUARE and NOISE for input 1, and NONE or the same LFO for input 2 - then choose DIVIDE as operator and set the AMOUNT to ZERO, then you will get a Bipolar SQUARE waveform with a start phase that depend on the choosen waveform.
EDIT: Arturia could add a Bipolar Square waveform though. They have allready added a falling SAW and a SINE it look like. EDIT END