Can anything other than acetaldehyde cause apple smell?

I posted something along these lines in the fermentation & yeast forum, but I'm not getting much in the way of advice/replies. My last batch of beer, a honey wheat, has been bottled since June and the last three bottles of it I've opened have had the aroma of green apples. I know from reading around here that the most likely cause is acetaldehyde, but here's where it gets tricky. Before now, this beer has not had this aroma. Could it just be getting old or stale? Is it infected? Should I throw away the bottles that it is in or could I reuse those after soaking them in sanitizer/bleach? The recipe is in the original post here:

https://www.homebrewtalk.com/f163/off-aroma-after-few-months-bottles-196747/

EDIT: the flavor is still fine, I don't detect any apple in the flavor, and it seems to go away if I swirl the beer and get the yeast back into suspension, but that could just be the character of the yeast masking the other off aroma

Check out the below link.

http://www.winning-homebrew.com/acetaldehyde.html

According to that link, acetaldehyde should age out after a period of time. This beer did not have the aroma when fresh, but now after three months in the bottle, it appears. The only corn sugar I used in this batch was for priming (3/4 cup), and that amount has never caused this to happen before...curious.