Chemi‑Con KYB drifting up in capacitance?

[LongRunner]

When the APFC in my IP-P300BN7-2 failed (again!) and violently blew the 180μF 400V Chemi‑Con LXS (my replacement for the original OST SPS), I tested the secondary capacitors upon salvaging them to be on the safe side. Most (Panasonic FR, Rubycon YXJ/YXS/ZLJ) are healthy but I found that the 3300μF 6.3V KYB I used on +3.3V has risen to ≈4000μF; I went ahead and measured my 7 unused spares from the same batch, getting very much the same result on all of them.
My 2200μF 6.3V KYBs (5 spares) from the same time are a similar story, measuring consistently ≈2750μF.

My 2200μF 16V KYBs (6 spares) from the same time are still good – as are the 1500μF 16V KYB I used on +12V, and a 680μF 16V one I purchased earlier – so maybe the issue only affects 6.3V KYBs (I don't have any 10V KYBs to test), or maybe it's a matter of luck. Is it possible that Chemi-Con focused too much on operating performance at the expense of shelf life (they only claim 500 hours at 105°C for it and their other aqueous series, after all)? If it was just the 3300s I could have reasonably dismissed them as a poor batch, but the 2200 and 3300 pieces I have are clearly from different batches so that explanation doesn't convince me.
It's not just a problem with 6.3V electrolytics in general, as my 1000μF 6.3V FRs (one used on +5V and 8 spares) are all within ±10% and even three of the original green‑sleeved 4700μF 6.3V KZEs (removed from a Socket A mainboard, hence >20 years old) are well within tolerance.
Even old mainboard-grade capacitors have remained within tolerance after over a decade of storage, so it's really concerning to see this from young KYBs
Anyhow, as a precaution I'll go with other series for future purchases (definitely for the 6.3V or 10V, and also for the 16V+ unless only the KYB is in stock)…

[Behemot]

Can have a look when I open something where they ran for some time, but I'm not aware of any problems.

This often happens when their leakage rises, the meter is than fooled and reports that as higher capacitance, depends on what meter do you use.