I'm not surprised to see these cells charging to 4.27V or even 4.3V, 4.2V protection circuit or not.
Bear in mind that the acceptable tolerance on charging to 4.2V is ±0.05V, and the protection circuit will have a tolerance of its own. It wouldn't surprise me if the protection circuit tolerance was also ±0.05V.
Given that this is the case, the protection circuit will be targeted on a trip voltage somewhere in the range of 4.25V to 4.3V. This ensures that it will still allow charging to 4.2V in the worst case of low tolerance, and perhaps a bit more for chargers that go a little high but stay within the acceptable range.
It has to be this way; if the protection circuit were targeted on 4.2V, you'd have cases where users were unlucky enough to get a cell with a protection circuit whose trip voltage was as low as 4.15V. Cue unhappy users and returned products.
Of course, this means that the protection circuit could allow charging to a voltage as high as 4.35V in the worst-case combination of manufacturer decisions and high tolerance.
That's the reason why one should never rely solely on a protection circuit to terminate charging, as some of the worst charger designs and ill-advised improvisations do.
The protection circuit is not there to regulate a normal charge; that's the charger's job.
The protection circuit's job is to help safeguard the cell's user in the event of a potentially catastrophic problem, such as an outright charger failure (e.g. a short-circuit dumping the full 5V or 12V power supply voltage across the cell) or a user error (e.g. accidentally installing a cell with reversed polarity in a set of three or more cells in series).
From that perspective, it doesn't matter if the protection circuit permits a slight overcharge, despite the fact that this will shorten the cell's service life, and compromise its safety in use if the overcharge is repeated too often. It's just like the way a household fuse rated at 13A might not blow until 13.5A, but that's not an issue as long as it's guaranteed to blow in the event of a short-circuit (which will try to draw a great deal more than 13.5A).
Personally, I rather like the idea of a 4.35V cell with a 4.2V protection circuit. I'd happily charge it to 4.2V every time, trading a bit of capacity for the noticeably longer service life and slightly increased safety of not charging it right up to its rated limit.