The last recipe I did:
Grain bill is 75% 2-row, 14% Maris Otter, 11% Crystal 20. Citra .01 oz. @ 90min, .75 @ 30min, 1.70oz whirlpool for 1 minutes, and 2oz dry hopped.
90 minute boil with no difference in mash or sparging.
I use whirl floc with 10 minutes left in boil.
I leave break material in the kettle by siphoning out of kettle into better bottles.
"post boil after a short time" means that I pull a sample when the wort has cooled down to about 100F. After maybe 20 minutes the proteins bind and sink to the bottem of the tube leaving the wort clear.
It could be some bug. I used a new siphon on the last batch. I don't really taste anything negative.
Chilling does not make it worse, maybe slightly better after a while.
I must reiterate: it has been over the last few batches I've done.