Not one to brag but I got an odd infection. Did a pseudo light lager I’ve brewed before but had to use a bottling bucket in a pinch for a fermentation vessel. You guessed it, infected! Attached is a pic of the yeast cake as it fell to the floor of the fv, odd! It has zero head retention, taste very odd almost medicinal but not the classic bandaid flavor, odd phenolics, no pellical or other infection indicators but it’s a dumper!
Your description points to wild yeast as the culprit. And now there’s a ton more of it in that bucket. Scrub it well (non-scratch sponge), give it a long soak with hot alkaline cleanser (hotter the better, just don’t melt the bucket), and then give it a long soak with extra-concentrated iodophor. Should be good to go after all that.
And take apart the spigot and do the same to that of course.
Spigots are where I have had issues the few times I have had a problem. I have paid special attention to them for the past few yrs without any further problems.