I confirm. With the transition to 11 Corona, I started getting random NaN errors. Moreover, they can be caught even on stage in gray material. And the more complex the scene, the longer you work in it, the more often you catch the NaN bug.
The same thing happens in 11.1 Corona. The error is present on all 3 of my computers.
For all those who are trying to catch this bug: I did not find any patterns that would help catch it. It's like random. Relatively speaking, I can work in a complex scene with a lot of suns and artificial light and everything will be ok, but I’ll catch NaN in some kind of closed corridor, which is essentially just a box. And vice versa.