While reading this had the same thought.... grounded has the solution (nice unintentional pun there with the name btw!)
Ask the CC for a few coffee bags (still in foils) whenever it happens open one and hang it nearby, it helps. (Of course only works with 'pillow packs') I do recall the same issue on other types as well.
It could also have something to do with the pax profile/catering being served... if you fly to/from destinations which partake in foods which are particularly fragrant, you will notice more - ahem- 'aftereffects' on those flights than on others. Not generalising but spicy foods/curries/stews with lots of garlic will do it every time... you could also use the trick of some scented lotion up the nose... works for me!!
