I noticed several times now, that, when I have a tag filter open, I get a bar telling me that new questions have arrived (example would be https://stackoverflow.com/questions/tagged/c%2b%2b but it doesn't really matter, because this behaviour is the same for other tags as well).
When you click on that bar, the questions appear in the list. But when I hit the refresh button on the browser, those questions are suddenly gone. When I hit the refresh button a littler bit later again, the questions are back in the list.
Is this a bug or a problem with cache timing in the browser (using Firefox)?
I noticed that, when I hit refresh several times, there seem to be some delay included, probalby to avoid server strain. Might be a side effect of this.
update
I just tested this on Meta and there this does not happen. So it seems only on SO.