The ansible MIDI support is capable of pitch slew (glide/portamento) but that can only be set via teletype - there is no way to enable/disable via the front panel or via MIDI.
Is it possible that the glide/portamento could be coming from your MIDI keyboard or your VCO? Do you only notice this in the mono voice allocation mode?
My recollection was that pitch slewing is turned off by default and a quick check of the code appears to confirm this:
…not necessarily, not every voice has to have the same timbre.