I was trying out 1.0.11 with rescript 11.2-beta.2 and it found a few circular deps that are indeed circular, but aren't causing an error with just rescript.
In the first case I have two modules A and B, both with .resi interfaces. Module A defines a polymorphic variant t, and some private functions inside it that was calling functions in module B, and then B references A.t, but only explicitly in B.resi.
B.resi
let myProblematicFunction: () => result<'a, [> A.t]>
Honestly I'm not sure why it would be compiling before, I hadn't noticed it because rescript would tell you about it.