Tyre lost a load of air, now it's seemingly fine?

[Acuity30]

Went for a drive, noticed vibration in the wheel so pulled over, tyre looked almost flat. Crawled back home and checked, 10psi.
Put it up to 35. Next day (today) it read 30, albeit using a different device to measure it so may not be correct.
Went to kwik fit (I know I know, but my local one is actually not bad), they did the usual spraying soap water all over it and inspected, no leaks. The guy overinflated it to 40 and just said keep an eye on it but he couldn't see anything wrong.
Any idea why it lost so much air and now seems ok? I did hit a couple of moderate potholes a few days before, maybe that large amount of flex let a lot of air out suddenly then it sealed itself up again?
The tyres are only about 2 months old, new valves were fitted at the time.

[Pica-Pica]

I imagine you hit a kerb, or by way of the pothole, unseated the tyre bead away from the rim. The over-inflation got the bead back into decent contact and sealed the air in.

[996TT02]

Valve can also seat incorrectly, did you check or inflate tyres just before (nominally) the one tyre went near flat?

I had that happen once, thought it was a puncture then inflated and nothing heard of since.

[Acuity30]

Pica-Pica said:

I imagine you hit a kerb, or by way of the pothole, unseated the tyre bead away from the rim. The over-inflation got the bead back into decent contact and sealed the air in.

That would probably explain it, will keep an eye out anyway.
Overall pretty happy with Goodyear Efficient Grip 2 though, good steering feel in dry and wet

[Cold]

Do you think you may have upset a local eco-loon recently? Some of them aren't adverse to a bit of tyre tampering.

[OldGermanHeaps]

Are the rims corroded at all ? Maybe a bit was loose then flaked off