Resource Manager Primary & standby session not associated to a resource consumer group

Hello, I have created a DRM config,
while listing sessions, i can see that they are all associeted to the good consumer group except for one :

(the server on which i am using the DRM is a primary DB, its standby is named "thestandby"

sid serial username machine osuser status module resource_consummer_group

225    19007    PUBLIC            thestandby@mydomain    ora10gdb    inactive    oracle@thestandby@mydomain (TNS V1-V3)        (null)


the resource group is null, is it normal ?

thanks