I would like to point out that some beers of mine have done very well at a competition, only to have gone downhill for the next a month later. That happens to some beers fast.
I have also had a Pils that was over 40 first round, but was given a kind score of 28 in the second round, as I got hurried in the bottling, and it had Diacetyl, as did the control bottle That prompted me buy a beer gun.
At a local comp I got an 18 for a DIPA, that was loaded with Diacetyl. "WTF" I said when I read the sheets at home and pulled out another bottle, no Diacetyl. At the next club meeting no one could detect any Diacetyl. I just marked this down as a bad bottle, and have taken the action of being really thurough with cleaning the bottles, then baking in the oven at 375F for an hour to sterilize. Bad bottles happen sometimes.
This should point out that the beer can taste great from the keg at home. Getting it in good shape in front of the judges is a challange that you have to face if you compete.