I was looking for information on factory and aftermarket valve keepers/locks and came across this written by someone in response to another question relating to rocker tip to valve contact pattern. Is the below true? Specifically that if the valve rotates with good aftermarket locks, then the engine experienced valve float? I never thought so, but now question the truth to this.
By non-rotating setup, he means the aftermarket locks that have gaps between the locks when installed. He states the factory 4 grrove locks butt up against eachother when installed and allow slight rotation of the valve when installed. That doesn’t sound right to me , about the 4 groove locks.

This is what he wrote:
“A non rotating setup should never show signs of wear on the valve tip other than a single bar where the rocker arm rides. If you see multiple patterns on this setup the engine has been in a valve bounce/float situation where the spring is no longer controlling the valve. Visualize the spring more or less staying compressed while the valve continues to close, now it's just good will holding the retainer/locks/valve stem package together, and in this situation the valve will rotate.”