Reported here: https://www.mediawiki.org/wiki/Topic:Xuaiglruugbkbmlu
When using Vivaldi (in a new private window) I can move the sliders but the pages shown / diff won't change.
Screenshots show that the revisions in the diff and in the popup don't match: https://imgur.com/a/CDjtNB8 vs. https://imgur.com/a/4Eyl4fx.
The same user reports that it works in Firefox.
WARNING: It's rather likely this is the same issue or at least the same cause as in T352169: Unexpected click behavior on RTL wikis with browser zoom >100%.
To do:
- Ask and wait for possibly more information.
- Manually test in Vivaldi.