I noticed a strange behaviour regarding this question:
What is the difference between A<T extends B> and A<? extends B>?.
When I navigate to https://stackoverflow.com/questions/tagged/java, it's visible:
whereas in https://stackoverflow.com/questions/tagged/java%20or%20spring it's missing
In both cases sort order is "newest". Also screenshots show it happening on "xx mins ago" -> "1 hour ago" border, but I observed it when the following question was "xx mins ago" too.
I tried different browsers, so it doesn't look like a browser cache problem.