My game recently started running under 60 UPS, and it appears to be due to the anti creep/biter virus capsules. The show-time-usage debug view (under f4) shows mod-Krastorio2 alternating between 0.7 and 1.4 milliseconds per tick. Before I used the capsules, the game was running at 60 UPS with mod-Krastorio2 using around 0.01 milliseconds per tick. I'm going to roll back to an earlier save from before I used the virus capsules.

I think it lasts few minutes after you throw it and then goes back to normal. That's what happened to me.

I did get a lag spike when I first threw the capsule, then I saved and reloaded the game. The lag was better after reloading, but never went away even after over an hour.

It's normal is an expensive tool on big maps, after some time all will return normal.

The first time I threw an anti creep virus capsule, I experienced the lag that slowly returned to normal. A few hours later after all was normal I threw another one to knock down their evolution factor. There was already no creep on the map, but the lag was back. Checking time usage in mod-Krastorio2 after about an hour, there was no improvement in time spent.

To test a hunch that something was going wrong because all of the creep was already cleared, I console spawned a small patch of creep. Afterwards the lag immediately improved and started to progressively clear up as I experienced previously. It seems like the virus is getting stuck looking for creep if there is none on the map and never stops itself.

Hi Grumblesxl,
Thanks to ur more accurate description of the problem, I found a bug in the script.
Fixed in the next version! (0.9.15)