I also determined through testing that the error is resolved by either removing code like "|JPN|1986 Asian Games}}", deleting the "MedalistTable" template, or removing "}}" from the code "{{KOR}}<br>Choi Myung-jin|KOR|1986 Asian Games}}".

In T420130#11711257, @Tacsipacsi wrote:

I took “any mobile device” (an Android 16 phone with Firefox 148), and couldn’t reproduce this on Обсуждение:Сент-Клэр, Дейн. Please be more specific:

• Which operating system (including version)?
• Which browser (including version)?
• On which page?
• Can you reproduce this in safe mode? If not, it’s probably caused by a gadget or user script (or sitewide script) interacting with DiscussionTools badly.