Traefik 3.7 service middleware feature tested, reveals syntax error in official example

A user tested Traefik 3.7's new service middleware feature, which allows applying middleware to specific backends like a canary instance. The official blog post's configuration example contained a syntax error, placing the 'middlewares' key inside the 'loadBalancer' block. The correct syntax requires 'middlewares' to be a direct sibling of 'loadBalancer' on the service definition. Once corrected, a test with a weighted service confirmed the feature works as intended, applying headers only to the designated canary backend.