Snaps are on and sometimes do not display when selecting Point to move from during Move command:
Note that Rhino dropped a marker under the cursor while it was briefly stationary during the Point to move selection. This can be seen south east of its current location.
After cancelling and rerunning Move command, with no other changes, the same selection shows the snaps correctly:
Rhino 7.7.21151.13001, 2021-05-31 (with Grasshopper running but minimised and with preview off. Grasshopper references the point being moved).