This is incorrect - as the regulations state:
5. A player that was:
a) granted a change of association; and
b) was not fielded in a match in any (official or unofficial) competition in any kind of football by the new association,
may request a change of association back to his former association provided he continues to hold the nationality of such association
By the terminologies of official, unofficial, competition, and kind of football used in the explainer, this means that if a player changes nationality, and then plays ANY game (friendly, or in a competition) at ANY level (this would theoretically include beach football, futsal, any underage group, etc), they are locked in.
For the avoidance of any doubt, FIFA doesn't set a nationality for international football for a player UNTIL they play an official match (non-friendly) at any age level. So if a player is selected and plays for U20 friendlies before anything else, they can be selected elsewhere later on in an official capacity for their dual nationality, and then that second selection is what initially ties them to that nation. THEN, should they wish to go back to their initial nation, they can - but only once.