This appears to be a css bug which (I think) has recently been introduced. It's most visible when viewing questions on Stack Exchange sites using mobile devices (the full site with responsiveness, not the mobile site) but can easily be reproduced by resizing a browser window on a question where the combined width of the tags is large.
A couple of example questions show this behaviour:
On Meta Stack Overflow: Why are questions based on misunderstanding about a tool closed as “no longer reproducible”?
On Meta Stack Exchange: Please notify us when a question we ask or answer is closed or reopened
Using the Meta Stack Overflow question to demonstrate (as the total width of the tags is larger):
At 1100px, the tags just about fit into their containing
div
.At 800px, the tags appear on top of related questions:
At 450px, the tags are now wider than the view (the last tag is completely off the screen), causing scroll bars to appear:
This doesn't happen to lists of questions - the tags flow onto multiple lines:
Reproduced on: { Firefox 81, Chrome 84, Edge 84 } on Windows 10, and Chrome 85 on Android 11.