The bad value seems to generate at the first time step immediately. But I have been unable to find if its present in the 0/ file. Thank you for tour advice so far! I think what I will do is use all the things youve mentioned and investigate them deeper/collect more examples. By any chance do you think the problem could be that interCondensatingEvaporatingFoam cannot handle closed boiling vessels like this? I might look into researching this alot more but I dont see anything in the source code that should make it behave like this…