bug: the configuration of the plugin bound to the service is not updated

[tzssangglass]

Discussed in #8475

^{Originally posted by MekelCon December 7, 2022}
Version info: APISIX 3.0.0

I try to use route, grouped inside a service using the Admin API.

I created the service A with a plugin config 1:
{ "plugins" : { "pluginX" : { // plugin config 1 } } .... }

Then i PUT my route Foo with service_id A as reference :
{ "service_id" : "A" .... }

Later when I update the Service A with a new config plugin config 2:
{ "plugins" : { "pluginX" : { // plugin config 2 } } .... }

I expected the new plugin configuration to be up to date when calling again the route Foo but i appear it is not the case, the config 1 still apply.
I have to PUT again one of my sub route to make it up to date with latest service plugin config.
Is it a normal behavior ? Am i doing or expecting something wrong ?

Thank you for your help.