Upgraded to 2.10.5 now none of my app config files work

Traefik Traefik v2
1

I am getting the following type error on all my app config files after updating from V2.7 to 2.10.5.

"the service "║24║ebook-rpi-svc@file" does not exist" entryPointName=https routerName=ebook-rpi-rtr@file

Here is the config file that works under V2.7

http:
  routers:
    ebook-rpi-rtr:
      rule: "Host(`ebook.{{env "DOMAINNAME_CLOUD_SERVER"}}`)"
      entryPoints:
        - https
      middlewares:
        - chain-oauth
      service: 
        - ebook-rpi-svc
      tls:
        certResolver: dns-cloudflare
  services:
    ebook-rpi-svc:
      loadBalancer:
        servers:
          - url: "http://192.168.0.116:8080"  # or whatever your external host's IP:port is
2

The nested use of " seems strange, using 4 in a row:

rule: "Host(`ebook.{{env "DOMAINNAME_CLOUD_SERVER"}}`)"
3

It is strange, but it works in 2.7.