Duncan Scott refused to acknowledge gold medalist Sun Yang after claiming a share of bronze in the men's 200m freestyle at the World Aquatics Championship in Gwangju.
The Chinese swimmer - who has previously served a doping ban - won the title only after his rival Danas Rapsys, who touched home first in one minute 45.78 seconds, was belatedly disqualified for a false start.
Scott - who dead-heated with Russia's Martin Malyutin behind silver medalist Katsuhiro Matsumoto of Japan - observed the national anthem but then stepped off the podium and refused to engage with Sun.
On Monday, Australian Mack Horton refused to share the podium with Sun after taking silver behind the Chinese swimmer in the men's 400m freestyle event.
Aside from his previous drugs ban, Sun currently faces a hearing at the Court of Arbitration for Sport over a decision to clear him of a further doping offence, and many of his rivals believe he should not be competing.
Having ignored Horton's gesture, Sun appeared more animated by Scott's stance, turning and appearing to mouth something towards the 22-year-old as they left the stage.
The bronze medal was the fourth of Scott's career and his first in an individual event, having earned gold as part of the 4x200m freestyle relay squad in both 2015 and 2017.