My sourdough croissant dough is too strong!

I'm working on my sourdough croissants and everything goes well until I hit the final shaping. I am using a home dough sheeter and roll the dough to 5mm (the sheeter is very precise), but then it immediately snaps back to 10mm. I try to roll it out to 20 inches, but all I managed today was 14 so I have a bunch of very narrow and fat croissants. The issue is the dough is way too elastic. Today I waited about 7 hours between the final lamination and the shaping to give the dough time to relax, but it didn't help at all.

Here's a bit of my process that I suspect is most relevant: 

- The hydration is 49.2%

- I mix the dough for 12 mins

- I rest the dough 4 hours room temp to give the sourdough starter time to multiply, then I stick it in the fridge overnight. The next day I laminate and shape, then warm ferment overnight, and bake the next morning.

I'm following this recipe and process (though I do 3x letter fold and I scaled up the ingredients): https://youtu.be/vgauxG8moUg