On the SwiftUI team we had a joke: "all bugs are bridging bugs."
It's hard to build a declarative layer over UIKit! There's a lot of undefined behavior, especially in the subtle timing of the update cycle. And it's always changing.
Even sitting in the same hallway, with an explicit goal of keeping the two frameworks in sync, we couldn't do a perfect job.
I can only imagine how hard it's been for the React Native team.