I am trying to build x86_64 packages on aarch64 using QEMU + binfmt_misc, but evaluation keeps failing.

Jul 12 21:48:56 hydra-evaluator[16842]: (project:job) Evaluating...
Jul 12 21:49:07 hydra-evaluator[16842]: hydra-eval-jobs returned exit code 1:
Jul 12 21:49:07 hydra-evaluator[16842]: warning: unknown setting 'allowed-users'
Jul 12 21:49:07 hydra-evaluator[16842]: warning: unknown setting 'trusted-users'
Jul 12 21:49:07 hydra-evaluator[16842]: Collecting from unknown thread
Jul 12 21:49:07 hydra-evaluator[16842]: child process (16944) killed by signal=6
Jul 12 21:49:07 hydra-evaluator[16842]: error: unexpected EOF reading a line

Has anyone seen this before?