This happens to me on Direwolf 20 1.19.2

Quark: Quark-3.3-374.jar

Full Spark profile: https://spark.lucko.me/CxDJhluS1V

This may be related to this pack using Oh Biomes you Go, which in turn uses Terrablender. (https://www.curseforge.com/minecraft/mc-mods/oh-the-biomes-youll-go). Maybe this just increases the complexity of finding the biome? I am just guessing here.

Yeah that is it...
I dug a little deeper. It searches for a specific biome, apparently. And in my world, that biome is very far away.
Searching for it takes 7.5 seconds and stalls the tick for that long.

Thanks!

The fix just moves the lag spike to when the stoneling is killed (from when it spawns), making it happen far less often. Still, if the server lags significantly whenever a player kills a Stoneling, the workaround described in #3561 can be used to fully prevent the cause of the lag spike:

Try disabling "Weald Pathfinder Maps" in the Stonelings module in the Mobs category in the Quark config file.