The election commissioner for Saxony has said that the seat tallies published in preliminary final results gave one too many seats to the CDU and AfD, and one too few to the SPD and the Greens.
The state's election commission said a software failure had led to the publication of the erroneous data.
The change is significant in that it means the AfD is on course for 39 seats, not 40. In the 120-seat chamber, possessing 40 seats would have meant the AfD could have blocked any legislation requiring a two-thirds supermajority by itself. Now it would fall one short.
However, the chances of future governments in either Saxony or Thuringia passing or seeking to pass such supermajority legislation in the coming years does not seem particularly high given how difficult it will likely be just to find coalitions wielding simple majorities.
Monday's announcement boosts the SPD to 11 seats, the Greens to 7, and pushes the CDU down to 41.