REST API endpoints randomly return 'restful get permission required' despite correct config

Problem/Motivation

We have implemented a custom REST API at the path /api/CMSDATA_product_aum_and_key_measures, provided by
the plugin custom_aum_rest_resource. We have also noticed the same behavior with REST APIs exported via
Views.

When accessing the endpoint, the following error is intermittently returned:

 Drupal\Core\Http\Exception\CacheableAccessDeniedHttpException: The 'restful get custom_aum_rest_resource' permission is required. in Drupal\Core\Routing\AccessAwareRouter->checkAccess() 

Strangely, this issue is not limited to custom REST plugins — it also affects RESTful Views exports at random. In all
such cases, the issue appears and disappears without any changes to the codebase or configuration, suggesting a
possible caching or access check bug.

Currently, we do not have reliable steps to reproduce this issue. It appears intermittently and is temporarily
resolved without making any direct application-level fixes.

Steps to reproduce

Note: The issue is intermittent and cannot be reproduced.