In ProSeries Basic, I had 2 dependents listed on the parents return, a carryover from 2019. I deleted the top dependent, to file their own return, but left the second dependent on the second line. Only 1 dependent showed on the 1040, BUT since line 1 was blank, the recovery rebate credit calculated another dependent and added $1100 ($500 + $600) to the return. I had to move the dependent up to the first dependent line in PART III Dependent Information.
I know in Professional, you can Right click and Delete Line in Table for things like that, it would have deleted the first dependent and line completely, moving number 2 up to that spot.
You should check if Basic has a similar function.
Good point. I don't know if those other folks just deleted the data for the kid or if they actually tried deleting the data line.