Hey CA crew,
I'm playing on vanilla, with no mods, on v1.8.2 build 13152.1837524.
There's a bug in Skarsnik's Prodder Quest which prevents player from completing its 2nd battle - Skarsnik's Prodder (2). I've found similar threads dated back in December 2019, as well as those for a similar quest battle for Clan Angrund in roughly the same location.
Attempting to use teleport to complete the quest will result in freezing and crashing of the game.
Attempting to initiate the battle by walking Skarsnik's army to the quest location is also impossible, as the quest location is deemed inaccessible when the mouse cursor is hovered over the quest location. The path finding of the army can only go "around" the quest location instead of going "through" it, so the quest battle can't be triggered at all.
I've attached my save game for your reference. Please look into this, as well as the similar issue with Clan Angrund quest battle.