It maybe has to do with the snow tiles. You said that the lag was only present when you reached the surface, so there has to be something out of the ordinary on the surface in a cold taiga biome that causes the lag. The only difference between normal taiga and cold taiga is the snow. Maybe the snow tiles are the culprit in this case.
It maybe has to do with the snow tiles. You said that the lag was only present when you reached the surface, so there has to be something out of the ordinary on the surface in a cold taiga biome that causes the lag. The only difference between normal taiga and cold taiga is the snow. Maybe the snow tiles are the culprit in this case.