Move not picked up by server

In this game en.lichess.org/ULx0ZsdXiIpu I played Kd8 with over 10 seconds left on my clock and then had to sit and watch as my time ran down despite being able to see the move on my board.

I've also run into this issue a few times. Incredibly frustrating. I made a thread here with a screencap of it happening as well: en.lichess.org/forum/lichess-feedback/finally-screencapped-the-my-time-running-down-after-i-made-a-move-issue#1

To try to tie down a common theme, was Kd8 a premove for you?

Not a premove for me, no. Also I did not get the normal red "reconnecting" text in the top right corner, in this case.

Very likely still a connection issue.
If that happens to you again look here en.lichess.org/lag
whether you're lagging.

I think it's unrelated to lag. I was in no way lagging and was able to open up new and perfectly responsive windows to Lichess as it was happening. As well I've had this happen multiple time and refreshing solves it every time, but in that case my time was so low that refreshing was as good as resigning.

It looks like a clear server synchronization issue. As soon as my flag fell, which presumably triggers a new state, everything became instantly responsive again. And again this is not a one off thing. I've had it happen multiple times and it's the same case every time.

Whenever this happened to me I would just wait a few seconds and the problem would just disappear. So I am not sure what's different there. (though waiting might not be an option when you're low on time; but for me it never was more than 5 seconds delay or so and also rarely more than once per game)

I also feel like this isn't just down to normal lag, in my case there was no "connection" error message (in fact, I made the move and then sat back thinking about my opponent's response, and it took me a good while to realise that my time was still running down). I also experienced the same behaviour as OhNoMyPants, in that as soon as the clock run out the connection worked fine. It was like the server never received my move but locally the board seemed to think the move was done.