Olympic champion Adam Peaty and British champion Sarah Vasey have criticised organisers for "ridiculous" timing errors at the British Swimming Championships in Glasgow.
British Swimming said timings in three 50m sessions were incorrect by 0.10 seconds, including Peaty's heats and Vasey's final on Tuesday.
The issue was fixed by Wednesday.
A similar incident at the same pool occurred at the 2018 European Championships.
The 24-year-old, who won gold in the 100m breaststroke at Rio 2016, said: "Happens once then it's a simple mistake, but when it happens twice it just becomes infuriating for the athletes."
Vasey, who won gold in the women's 50m breaststroke in Glasgow, tweeted: "Sorry, but this is ridiculous. Imagine becoming British Champion then finding out two days later you actually went 0.1 slower... oh wait I don't have to imagine."
British Swimming says it ran "extensive tests and reanalysed" race results and confirmed the issue affected times recorded in the 50m races during two sessions on Tuesday and one on Wednesday morning.
A statement said: "Whilst we are extremely disappointed to find ourselves in this position, we are pleased that this issue was able to be resolved before the evening session on day two of the championships, and we are confident that there will be no further issues during the championships. "
Scotland's Duncan Scott broke his own British record as he won 100m freestyle gold on Thursday, as competition at Tollcross continued.