Some seats at Olympic venues have been replaced or welded properly in to place after sports fans complained they collapsed beneath them.
The complaint came from spectators who went to the archery at Lord's and rowing at Eton Dorney.
London 2012 said there was a problem with the welding of a couple of seats, which come in a set of four, and there was no collapse.
All of the 200,000 temporary seats at the Olympics have been checked and less than 100 have been replaced.
A spokesman said: "The welding on one seat came away.
"Overnight they have gone through all of the seating that this particular contractor put in place across the whole games (venues network)."
The spokesman said that spot welding at the Lord's venue may have led to a seat that "falls slightly forward".