Move made during classical game didn't register

I was playing this mostly hopelessly lost game lichess.org/JK90f1dLFIKh and made a move Rg4 with about 1 or 2 minutes left. Shrotly afterwards, without warning, I lost on time.

The only indication I had that there was a possible problem was that my opponent's time was not decreasing, and that he was needlessly giving me time on his own turn. Somehow the move didn't register on the server, but showed up the regular way on my browser (ie. it wasn't a purple square indicating it was a premove or anything like that).

This is the first time I've ever experienced this. My internet connection seemed stable throughout.

"My internet connection seemed stable throughout."

Your Game Completion Rate in your profile is no longer 100% so I would say you were definitely not connected to the server for those last 1 or 2 minutes of the game. Your internet may have been stable, but your connection/link to Lichess did not appear to be.

Happens sometimes. Maybe due to lichess maybe due to your own connection. Your playing online.

I was still able to use the site without problem as I recall checking my opponent's stats during this waiting period, and my green online indicator was on throughout.

Also, I must have maintained some kind of functioning contact with the server as I was still receiving messages in the chat log indicating that I was being granted additional time, and I also received the loss notification the moment that my time ran out.

Barring any developer intervention, is there any way to avoid this in the future, aside from just being diligent by checking that my opponent's time is ticking down after every move?

Weird, I never had any connection problems on lichess...
An interesting note on the game though, 45...Rc5 would have still been enough for a draw (if you play on correctly) as he can't really advance if you block him.
EDIT: the position is even more interesting than I thought at first. On Rc5 if h5 black has to find Rc4+ Kg5 Kg7. If 46..Kg7 right away against h5 white wins with 47. Rg6+ Kh7 48. Kf3!!