User blog comment:Kirkburn/Technical Update: August 24, 2015/@comment-1038387-20150824202244/@comment-1038387-20150825114024

According to Bert:


 * Each reply actually does exist with its own thread ID number and can be viewed standalone using that (one of the many wonderful quirks of threads on Wikia). However, those individual IDs are not typically surfaced.


 * [...]


 * I suspect that the age of the thread might have something to do with it, we've done a couple fixes to caching and such for threads, during the year.

If you've seen it on other threads, please report it.