I was looking into Redjubjub.
I noticed the example in the readme does not seem to match the syntax of the implementation.
The redjubjub implementation requires a randomizer. However the example makes no use of such an element.

A small example:
reddsa::frost::redjubjub::round2::sign takes 4 inputs.
However your example (which redefines reddsa::frost::redjubjub as frost) shows frost::round2::sign takes only 3 arguments).