I was due to start my new job on Monday, in an analytical chemistry lab testing food products. On my pre-employment questionaire, which included some health questions, I stated that I used to be allergic to marmite. Since that contains quite a few common food allegens (none of which I'm actually allergic to) the HR department decided that it is too risky for me to work in the lab, since I would be working with those allergens on a daily basis.
The stupid part is I'm not even allergic to marmite any more, to test this, ealier I went and bought a pot and ate a big spoonful (disgusting), but had no reaction whatsoever, so now I've lost the best job oppurtunity I've ever had (at least so far, hopefully).
TL;DR: Denied a job in a food lab because of an allergy I no longer have.