config:

set service pppoe-server authentication mode local
set service pppoe-server authentication local-users username foo password bar
set service pppoe-server authentication local-users username foo disable
set service pppoe-server client-ip-pool default range 10.0.0.2-10.0.0.254
set service pppoe-server default-pool default
set service pppoe-server gateway-address 10.0.0.1
set service pppoe-server interface eth0

disabled user is still in allowed list, new sessions from the user get established

{F92514343}

There is a typo in the config key name: the template uses user_config.disabled instead of user_config.disable. Because disabled never exists, the filter user_config.disabled is not vyos_defined is always true and disabled users are not excluded from chap-secrets:

data/templates/accel-ppp/chap-secrets.config_dict.j2:
{% for user, user_config in authentication.local_users.username.items() if user_config.disabled is not vyos_defined %}