The request with updated task states

No bearer token, or the token could not be parsed.

The two do not read identically. A request with no token gets the
envelope below with the message
"Authentication token is missing or invalid.", though its
timestamp carries nanosecond rather than millisecond precision. A
token that is present but unusable (unparseable, or missing sub /
tenant_id) is answered with a default error body that carries a
path rather than a useful message.

The caller's sub is not in the task's approverIds, or it
matches the request's initiatedBy (four-eyes).

No such resource in the caller's tenant. A resource that exists in
another tenant is also reported here.

The task is already acted on, or an earlier step is still pending