"Invalid type Exchange for attribute value. Expected one of `bool, str, bytes, int, float` or a sequence of those types" warning when Celery task runs another celery task

Celery custom configuration:

from kombu import Exchange, Queue
exchange = Exchange('custom_exchange', type='direct')
queue = Queue('custom_q', exchange, task)
class Router:
    def route_for_task(self, task, *args, **kwargs):
        return {
            'queue': queue(task),
            'exchange': exchange,
            'routing_key': 'my_key'
        }

Steps to reproduce
Run celery task from another celery task.

@celery.task()
def task_1(*args, **kwargs):
    task_2.apply_async(*args, **kwargs)

What is the actual behavior?

[WORKER / WARNING] Invalid type Exchange for attribute value. Expected one of ["bool","str","bytes","int","float"] or a sequence of those types

Reproduce the warning with the custom Router, Exchange, Queue, and the task_1/task_2 apply_async flow shown in the issue. Trace how the routing result is passed when one Celery task runs another, then verify that the reproduced flow no longer emits the invalid Exchange-type warning.