I've never seen this in 6 years of making starters. After 30 plus hours in the fridge, my starter still has about 1/4" of foam on the top.
I used a 3 liter flask to make 2 liters of Imperial Flagship yeast. I boiled water in a pristine clean flask the night before, covered with foil and let it cool overnight. Then I added 2 cans of Propper Starter (I've used this 4 times before) and noticed it was foamy but the starter kicked off fast (it is Imperial after all). 24 hours later, I cold crashed. There was foam but not the type you see in krausen. It's been in the fridge, smells and looks fine otherwise.
So, RDWHAHB?
I used a 3 liter flask to make 2 liters of Imperial Flagship yeast. I boiled water in a pristine clean flask the night before, covered with foil and let it cool overnight. Then I added 2 cans of Propper Starter (I've used this 4 times before) and noticed it was foamy but the starter kicked off fast (it is Imperial after all). 24 hours later, I cold crashed. There was foam but not the type you see in krausen. It's been in the fridge, smells and looks fine otherwise.
So, RDWHAHB?