Here is the change.
On Wednesday, the NFL announced some modifications to their rules regarding practice squad elevations for the 2021 postseason. Per a league-wide memo, all playoff teams will be allowed to promote practice squad players, regardless of their previous status as standard elevations. The move will provide teams with further player availability as COVID-19, especially as COVID-19 cases spike across the league.
I was going off of the regular season rules which said you can only be elevated twice. After that one has to be added to the roster. Since the rams activated both players for the first two playoff games, I assumed that we would not be able to send them down to the practice squad anymore. With the change to the practice squad activation rules for the playoffs, that is not the case.