I don't know what the IRS will rule on this matter.  Initially Congress intended that the $1,400 followed the taxpayer to whichever return they ended up on.  But the instructions for the return show just the amount the taxpayer received.

However this is different than students who miraculously all of sudden provided their own support in 2020.  College students did not qualify for first two stimulus, so they were not really double dipping as in in this case.