There have been reports of QR using the posting date rather than the flight date.

It is unclear which date in December that QR used to decide who out of those due to expire on 31 Dec had not yet requalified, but for all of those people (including you) they decided to grant a free extension for 3 months. If you had accrued 540 qpoints in your account between 1 Jan 23 and whatever that decision date was, you would not have received the free extension as you would have already earned enough to renew to (presumably) 31 Dec 24.

But you had not requalified by that decision date which means that, had they not given the extension, you would have been downgraded. So they probably did you a favour and you live to requalify another day on 31 March, provided you hit the points and minimum QR sectors requirements during the 12/24 months until then.

The only airline's flights that consistently credit to QRPC whilst you are in the air are those where you have a QR ticket on a QR flight. There is almost always some delay of days or weeks for flights on partner airlines to credit (as with all airlines), which makes relying on those right at the deadline somewhat risky.

The three month extension means you're probably a winner all things considered.