I will say it’s not a great walk mode. Keeping that button pressed at all times is a challenge when in tough terrain. It stops and then you press harder and it goes again after a delay. I love the bike but not the walk mode.
My experience is I put it in walk mode then repress and hold. Let the bike roll back a bit and it engages. However my neighbor’s specialized e-bike’s walk mode, is much easier, press once then press again and it goes.