The World Anti-doping Agency (WADA) is looking into possible integrity issues with urine-collection bottles that were redesigned after the Russian Olympic doping scandal.

WADA said it learned on January 19 less than a month before the start of the Pyeongchang Games, that the bottles could be susceptible to manual opening upon freezing of a sample.

Investigators found that Russians were able to secretly open bottles at the Sochi Olympics and exchange dirty urine samples with clean ones previously provided by an athlete.

That led to a redesign of the bottles, and WADA said that if there is, in fact, a flaw, it “will raise concerns and questions.”

Russia’s Olympic committee has been banned from the Pyeongchang Games, and this weekend, the International Olympic Committee said it had approved 169 Russian athletes to compete as “Olympic athletes from Russia.”