graphql-ruby: RuntimeError (can't modify frozen SystemStackError)

I’m in process of upgrading graphql-ruby from v0.10.9 to v1.2.6. Application has around 60 mutations and 40 types. It was a pretty easy process other than the 1 mutation which throws SystemStackError: stack level too deep. Resolve function of the mutation isn’t even called, so I believe It’s caused by the Graphql-ruby internals.

Anything you would suggest to debug this?