The page title <h1> content of Special:SpecialPages on mobile site is being replaced with the page title of a userpage including the registration date tagline.
I once noticed this, but there was no way to reproduce and it disappeared.
Now it seems to be somehow reproducible.
Link: https://en.m.wikipedia.org/wiki/Special:SpecialPages (Following this link on desktop didn't work for me for the first time. But it did on refresh.)
|Correct title on desktop site||Mobile site (not logged in)||Mobile site (logged in)||Mobile phone|
Browser is Google Chrome 95.0.4638.54 (Official Build) (x86_64)