I’m not sure what, but looks like something Looks like the glimmer topic list mode setting is hiding the topic solved status in the title line of Topic list pages on Meta - the code for the solution checkbox goes missing when that setting is enabled (thanks @Moin for pointing out which setting was doing it).
Meta
Topic list view:

Topic view:
Console:
On my hosted instance, where it is displaying as expected with Glimmer topic list mode disabled.
I am seeing it in multiple browsers, mobile and desktop, on my Macbook and Linux machine, iphone and ipad.



