OMG people...no one who is vaping has gotten sick from diacetyl. There was a total of around 21 cases, all before the mass comercialization of e-cigs. And all of them were smokers, not vapors. Given the test results that Five Pawns had near .25% Acetoin (which is off the charts for those that don't know, 2500ppm), also given that it had such a huge following you would expect to see forums all over the place asking if other people are getting sick off five pawns liquid. But strangely enough you don't...And why is that...because the doctor that got everyone so scared of diacetyl just happens to be a cardialogist, not a pneumologist/pulmonologist (lung doctor). If you have a heart attack do you see your optometrist for advice?
All that being said my best guess as to why your reacting to your e-liquid might just simply be a reaction to your extracts found in your e-liquid. It also could be made with organic ingredients which have a tendency to inflame the lungs. It could also be that there is still ethanol in the liquid that wasn't evaporated off after being mixed, or could simply be added for extra throat hit (I know at least 1 person who does this.) The other possible reason could be too little wick on your coil, or just that your running your mod too hot. Also you will get a harsh vape if you oversaturate your wicks when you drip. There is also the source of the extracts and nicotine to consider. Most stuff from china will mess you up, some even tested positive for ammonia (AKA. Cheap as F***). I would bet that it is one of these reasons well before you had any kind of reaction to diacetyl. Most e-liquids don't come anywhere close to the limit that NOSHA set which is 13ppm PER 15 MINUTES, UNDER STRENUOUS PHYSICAL ACTIVITY. (Vaping is rarely strenuous, and most people breath fresh air in between hits, just saying.)