Discussions, post-mortems, analysis, inflated egos, and all that jazz.

So, Dima Surmay stopped the game for the first time, but the reasons weren't given, and is that equivalent to griefing?

Griefing is precisely what those reasons represent. At the very least, it certainly can't be called correct behavior.
The story is simple, especially since things have unfolded this way.
In the first week, Dima Surmay leaves the game during BoLo's turn, saying he urgently needs to go. BoLo manages to save.
The game is resumed a week later. Both players have partially forgotten. Dima Surmay loads the autosave. BoLo makes a couple of moves and, remembering that there's a save from the middle of the turn, immediately leaves and informs him. Then, Dima Surmay refuses to continue, claiming that the opponent simply attacked someone and lost... Whether this can be called griefing or not is up to each individual to decide. If griefing is understood as incorrect and unjustified behavior in a game situation, then that's exactly what it is.