What is happening when some people answer a question (usually a meaningless or nonsense answer), but when you click on your question, to?

see their answer in more detail or possibly to flag their answer, their answer does not even exist then? What is going on? And why do people (the answerers) even bother to do this? What is the point? It seems to me, that they are just wasting their own time. Why do you think they do this? I don't see at all How it benefits them.
Answers

CarolOklaNola

Several possibilities. The answer may have been caught by the spam filter, your mobile device may not be in desktop mode, they may have deleted their answer, or the answer was reported enough times it was removed from the YA display. Notifications don't update.

Daniel

If you see Answers in Notifications but not the Question its Due to the Answer got Reported and Deleted after the Notification for it was Sent out Yahoo does not update there Notification when Someones Answer gets Removed

Zirp

non-answers are against the guidelines and will often get reported and deleted

.

Chronic point gamers often get their answers ghosted by the spam filter.