Sometimes there's a lag, during which time no questions will appear in a category (or several or all), then a bunch will appear at one time.
Or, your question may have been held back for any of a few different reasons ... when that happens, it will show up in the spot it SHOULD HAVE been in, had it appeared when it was submitted. That can be hours to days later, and several pages back ... or it may never appear at all. You can check the timestamp on your question and those beneath which yours appears ... you will probably see that your question is where it should be based on when yours and the others were submitted.
As far as questions 'ghosting' (appearing, disappearing, reappearing), I've seen that, but I have no explanation for it, sorry.
ADDED: I just looked at your question and the category homepage on which it is posted ... based on time of submission, your question is right where it should be, but WOW ... I refreshed that page 20 times, and your question appeared maybe 3 times out of 20. Doesn't seem to be affecting any of the other questions on that page, though.
You could make a 'bug report' on the Y!A suggestion board, if you wanted to ... the link is at the 'About' tab, top of the page.