Hi Leo,
1- Is not a cache problem
2- All plugins disable and still the same problem
3- Two of the sites are exactly the same, one staging and another production. In one it works, in the other one, not.
4- Now is working, but I need set every option again, every time I need make a change. And, only works in certain order, first I need set Page Hero, then Site Header, and then Display. If I change the order, does not save all the options that I did set.
5- When GP had legacy page headers, I had a similar problem, that was resolved with an update, a few months ago.
6- Because of the random of the issue, I think is a bug of GP, not the site.
I hope that infomartion can help. For now, is working but is not ideal because I need set everything again for every make a small change.