Why does an annotation error occur when clearing the cache?

Question

symfony

When clearing the symphony cache that runs after composer install, an error occurs:

In FileLoader.php line 166:
!!
!! Notice: Trying to access array offset on value of type null in /app/config/
!! routes/../../src/Controller/ (which is being imported from "/app/config/rou
!! tes/annotations.yaml"). Make sure annotations are installed and enabled.
!!
!!
!! In DocParser.php line 1002:
!!
!! Notice: Trying to access array offset on value of type null
!!

# config/routes/annotations.yaml
controllers:
    resource: ../../src/Controller/
    type: annotation

sensio_framework_extra:
    router:
        annotations: true

What's wrong here?