Having driven an EV for a few years - BMW i3 - (and followed numerous EV sites - incl Tesla) this is what I believe.
It is extraordinarily unlikely that any 'Unintended acceleration' takes place and certainly not in Teslas as detailed in their response and evidenced by software experts etc. Therefore I doubt the iPace has UA unless it has a fault - unlikely too as it will have checks and balances for this situation.
But I have been caught out in our i3 similarly to as described above. Cruise control set at a lower speed than one is driving, lift off and regen kicks in until the set speed is reached and then the car stops slowing on regen and it FEELS like the car has accelerated......if this happens as one approaches an obstacle, it can be unsettling and confusing! User error...
In reverse when looking over one's shoulder with feet hovering over the pedals to accelerate or brake, I have touched the accelerator instead of the brake momentarily and in tight confines that can feel like UA - driver error. Especially as regen can confuse the situation as well
Our i3 has a minor fault which BMW can't reproduce where the accelerator pedal occasionally doesn't completely go to zero on liftoff so the regen doesn't kick in (and the car will creep very slowly in traffic - irritating!) and this can feel like a failure of sorts in traffic - especially if one relies on regen.
I believe the main reason EV drivers report UA more than ICE cars is because the regen can fool some drivers into thinking that the accelerator pedal is a 'brake', so if the car at slow speeds is not slowing as required (on regen) the accelerator is pressed in error.
The instant and sound-free EV acceleration then takes drivers by surprise and they 'freeze'/panic rather than lifting off and/or braking (which will over-ride the accelerator whether they lift off or not). Of course if they then push the accelerator they will arrive at the garage door/fence/wall rather rapidly.
We have lived in a world of slow responding, noisy and non-regen ICE cars so long, our sub-concious driving instincts won't die so quickly. EVs are sold/bought and relished on this instant silent response but for many drivers it can be problematic unless they stay alert and adapt.
I even read a motoring review in the UK newspaper of an EV, where the reviewer claimed that regen braking was dangerous (and should be turned off!) because drivers 'relied' on regen and were not prepared to move their foot over to braking!! He said he was a safer driver because his foot 'hovered' over the brake when he needed to slow in an ICE car due to lack of regen.....No accounting for incompetents!