Bug: Correspondence games expire before they're due

I've recently had two correspondence games seemingly expire before they were due. "Seemingly", as I have no definite proof.

1. The following, played with a friend, had no time limit, and I was notified the opponent resigned. However, they say they have not resigned and that the game simply "ended".
en.lichess.org/CLm51gO9LQBG

2. The following had a 14-day time limit, but when I was notified that may time has run out, I felt like that wasn't the case. I couldn't see when moves were made, but was almost sure I had no red-coloured indications of games pending in my "games in play" tab.
See my question to the opponent in game page, although it hasn't been replied to.
en.lichess.org/ODK5N8uD

When did this happen? About three weeks ago, a whole spate of these happened, the big foot which thibault thought he'd fixed.

Damn swipe, didn't mean big foot, but basically, thibault thought he'd fixed it.

@Caustic This might not be the exact same issue... earlier games timed out prematurely.

Here apparently games are timing out without adequate warning: "I had no red-coloured indications of games pending in my "games in play" tab."

Game 1 terminated itself a couple of weeks ago - possibly at the same time @Caustic mentions. So if it's a one-off I guess there's nothing more to discuss or investigate.
Game 2 probably 2 months ago or so. I don't think we users get to see the timestamp. Haven't found it, anyway.

@Toadofsky, you refer to games with an expiry date. However, game 1 has no such date set.

@bz I'm unfamiliar with the game clock code or expiry dates; and I am unfamiliar with how to easily, reliably duplicate the issue and investigate what the code -- again, that I haven't seen before -- used to do.

I started conversation in the Lichess discord since honestly I have no idea what the code used to do, is doing, or should be doing.