P. 118 of the ISU Constitution speaks to protests and changing of results/scores: link. Note this paragraph:

"However, if the Referee learns...within 24 hours after the award ceremony that an incorrect

mathematical calculation occurred, the Referee may correct

the calculation even without a protest provided that the

Technical Controller, both Technical Specialists and the Data

Operator all agree that there was such an incorrect calculation.

If such correction requires corrections of the final placements

of the Skaters, the corresponding medals and/or awards shall

be changed accordingly"

So it appears they went outside the 24-hour window in this case, probably because the math error would have consequences beyond the GPF, if not corrected. Or, maybe the correction did take place within 24 hours, but the public is only just hearing about it now.