Noticed strange move - as far as I understand rules there is no choice of how many stones (hexes) one player should put.

And here only one hex was payed, while move should consist of two hexes.

He(gamesorry) beat me with the same trick.

I tried one thing in URL  and it works (i can put one hex instead of two):

URL after one hex put: https://littlegolem.net/jsp/game/game.jsp?gid=2174766&move=ff

Then change URL to this one: https://littlegolem.net/jsp/game/game.jsp?gid=2174766&move=ffff

It counts move in the same place. I wonder are there similar bugs in other games and the other question what to do in our current catchup.ch.25.1.1

I think it is not a bug - according rules it should be available.

Howevert it should be available in normal way.

kspttw is correct: it should be available, and is definitely legal according to Nick's rules. Unfortunately, it just hasn't been implemented properly. Though rare, there are edge cases in the endgame where playing 1 stone is a guaranteed win, but 2 stones is a guaranteed loss. This is the first time I've seen it used this early in the game.