[beerlord]

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?

[KellerBrauer]

Interesting phenomenon.  What is: RDWHAHB?

[Robert]

Interesting phenomenon.  What is: RDWHAHB?

Charlie Papazian's old mantra: Relax, Don't Worry, Have a Homebrew!

[KellerBrauer]

Ah!  I see. I’m reading his book and see that statement a lot, but never put it together. Thanks Robert!

[hmbrewing]

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?

Yup. RDWHAHB. I've never used Proper Starter but when I've made starters in the past I've had this happen. For some reason some foam just hung on. You should be fine. Especially if it smells and looks good.

[charlie]

...  24 hours later, I cold crashed.

It sounds like the starter wasn't finished, but I don't know if that matters.

I stir my starters on and off depending on their activity level, and find that it usually takes about 36 hours for them to finish. Then I crash them. But like I said, I don't know if it matters.

[beerlord]

I actually kegged this beer today after only 14 days. It over attenuated but still ok. The starter was, as expected, perfectly fine. 
I really don't enjoy beer so young but it's kegged and will be sitting there for 2 weeks to condition.
It's all good!