They need to stop the game and review the shot if they are going to. You can't just remove points several minutes later because it can change how teams play after that. Now it was probably early enough that it didn't alter the outcome, but the optics are very bad.
There are two reasons the review is conducted this way:
1) Reduce stoppages
2) Coaches can’t challenge no-calls, so there’s no way for the disadvantaged team to ask for an immediate review.
In the either the last two minutes or the last five minutes (I forget which) of the 4th, as well as OT, the refs stop play immediately, because knowledge of the score is considered crucial at that time, but before then it is not. And this is correct. No team is playing to the score early in the third quarter. If the Heat “lost momentum” because they went from being down 8 while the Celtics were shooting free throws to being down 11, when they had been down only five a few minutes earlier at the start of the half, then they have some very weird definition of “momentum”. The Celtics, who had the initial call go against them, didn’t lose momentum — in fact they went on a 9-2 run between the shot initially being counted and the reversal.
The whole thing is a bunch of nonsense. The NBA has it right already. Review an easily reviewable play at the breaks instead of stopping the action. Keep the game moving and adjust the score. If a team gets frazzled because they lose a bucket, they don’t have the mettle to win that game anyway.