Express Route circuit connection works only 1Vnet but not others Vnets

We hire a azure expert to setup the migration in azure. we have network issue that event the azure expert trying to understand.

-I have 6 VNETS, only 1 vnets subnet was advertise over BGP on premise. The rest i cannot see on premise.

-When i am checking the routing table of express circuit in azure i do not see others VNET subnet

-Also my BGP is not activate on Virtual Network Gateway, The azure expert saying that you don't need it

-I see only one connection with VNET and expressroute only

-we have a VNET for Palo alto where all the VNET will use has a default route . That vnet subnet not seeing on premise and not in routing table of express circuit in azure

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I check the configuration checklist by azure recommendation:

-My express route has been provisioned between on premise. for my Azure private peering

-Virtual network and a virtual network gateway created and fully provisioned

-Virtual network gateway for ExpressRoute uses the Gateway Type 'ExpressRoute

-1 virtual network is link to a standard ExpressRoute circuit.

-All virtual networks must be in the same geopolitical region when using a standard ExpressRoute circuit.

--I can ping end to end between on premise and remote subnet on azure express route

--We don't have the Default routes Azure private peering

where do you think missing or bug ?

thanks