All too common, I'm afraid. When I visited CocoView in Roatan a few years back I was asked to do some checkout skills in the shallows. The divemaster wanted me to kneel down, do a basic partial flood-n-clear, then do a basic reg recovery (I was in a long hose setup, which confused the bejeebers outta him).
In three feet of water I hovered a few inches off the bottom, removed my mask, put it back on, cleared it, tossed my reg over my shoulder, put my backup in my mouth, recovered my primary, switched back to it, looked at him and gave the thumb.
As soon as we surfaced he said, "now let's go back down and kneel on the bottom so I can make sure you're properly weighted" ...
... Bob (Grateful Diver)