manticle
Standing up for the Aussie Bottler
Sorry a little off the OP.
When you no chill your cube do you fill it and leave no air? If so you will have no head space so Krausen will certainly over flow. If not how much air do you leave, and aren't you afraid of infection / oxidation?
Fear_n_loath
Krausen won't overflow until there is yeast in there. Can't realistically put yeast in a no chill cube until it's cool and you've undone the lid at least once (to get the yeast in)
If you ferment in a no chill cube you (should) squeeze the air out when you first fill the cube and tighten the lid, then, when the yeast is pitched, let air in, aerate (I retighten the lid and shake) and put yeast in. No more risk of oxidation than taking the lid off a cube and pouring into a fermenter.
I think you missed something but it's strongly possible that I did.