US-05 off flavors

All the cider I've made so far with US-05 has this weird after-taste. It's kinda of a 'stale' flavor. My g.f. didn't notice it at first, but when I said "This tastes like old socks" she said "Dammit, you're right. Now you've spoiled it for me!" Any idea what it might be? I have made 3 or 4 batches and they all taste like this. (I've also made several batches with Lalvin EC-1118 and Cote des Blanc without getting this bad flavor; it's not that my technique is bad, I have no infections.)

Is it just that yeast? Many of you seem to like it. The only thing I can think of is that my room is about 19-23 C (66-74 F) which is on the upper end of the temperature range for this yeast. What temperature do you brew at with US-05?

That may be a bit warm for S05- at least a room of 75 degrees is too warm. But if it is like old socks, maybe you mean musty or stale? That could simply be from oxidation; that is, headspace in the fermenter once fermentation slows.

I find S05 really likes 65-68F. I've brewed good beers with it at 72-73 but it comes out cleaner in the mid to high 60s

What's your process and what is your recipe? How long do you allow the cider to age? I typically ferment apple juice using 71B or QA23 and have never had any off flavors but stressed yeast and as Yooper suggests , oxidation can produce unwanted flavors...

How much yeast are you pitching? I've gotten off flavors with us-05 by over pitching.

My very first batch used US-05 and it turned out pretty neutral. I have made a couple of others with S-04 but was told to make another batch exactly like the first with US-05. Mine was fermented around 20 C (68 F). I pitched a full packet in 15 L of juice.

I'm pitching by eyeball b/c I only have 1gal batches and I try to aim for 1/5th a packet per batch, but I may end up with more/less than that. I definitely wind up with headspace in my secondaries because I don't often have extra cider sitting around after I brew. So that's something I can change. I don't have much control over the temperature though. I'm not aging these long at all, I've never really let anything get past a month or two in secondary/bottle altogether. Would using a campden tablet at racking help with the oxidation, or do I really just need to tighten up on the headspace/splashing? (You know, maybe the problem is splashing. My siphon hose is a bit short, so the brew tends to spray onto the inner wall of the lower container as I fill it. That would be a problem, huh?)

My recipe: generally just filtered apple juice from the supermarket plus either sugar or concentrate to hit ~1.07-1.075. I threw some fruits/veggies into a couple (cranberry, rhubarb, pumpkin). Actually, the pumpkin is the most recent one and so far it tastes ok.

Here's a recent thread I found interesting

https://www.homebrewtalk.com/f39/us-05-fermenting-63-degrees-515811/