MiniZinc 2.8.4: FindMUS "multiple errors:"

[CervEdin]

Can't get minizinc --solver findmus to work in 2.8.4.

echo 'constraint true == false;' > model.mzn && minizinc --solver findmus model.mzn

multiple errors:

Possibly related commit https://gitlab.com/minizinc/FindMUS/-/commit/a8e426563de7cdd77a66fe1c4f1938f146244c6c

Works fine in 2.8.3

Warning: model inconsistency detected: expression evaluated to false
model.mzn:1.12-24

SubSolver: hard cons: 1 soft cons: 0 leaves: 1 branches: 0 Built tree in 0.02446 seconds.
Background is not satisfiable, exiting. Try using --soft-defines.