Thanks! @nmattia literally just helped me debug this (not all heroes wear capes) and while we did not find the solution, he found a workaround by encoding the argument in raw
#!/usr/bin/env bash
MANAGER=$(dfx identity get-principal)
dfx deploy console --argument "$(didc encode '(record {manager = principal"'${MANAGER}'";})' --format hex)" --argument-type raw
and making the argument mandatory
let call_arg = arg_data::<(ConsoleArgs,)>().0;
let manager = call_arg.manager;
Oh that’s a good idea