Your experience differs from mine. As you know, I also brew lots of sour beer and always in a clear fermenter so I can see the progress. I frequently see my pellicles begin to form with small white patches scattered across the surface.
Pellicles don't all start the same way or look the same.
Here's an example of a beer pitched with Wyeast Belgian Lambic Blend:
https://www.homebrewtalk.com/threads/what-is-this-on-top-of-my-beer.666037/I ran a little test to see what people would say it was, and unsurprisingly 90% were incorrect. There are some bubble rafts in the photo in addition to the white patches, which probably threw some people off.
I can show you the beer now if you like; it's still in the fermenter.