Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.
From your verbatim, I see
- You have a VPN Gateway in a HubVNET and this VNET is peered to multiple spokes.
- You checked the BGP Peering view of the HubVNET and you do not see the VNET Spokes being advertised
- But from a NVA in the HubVNET , you are able to see the routes for peered VNETs.
Summary :
- Seeing the NIC Effective routes in NVA and the VPN Gateway learned routes are not all related and you should not compare these two.
- From the spokes, did you enable Gateway Transit on the peerings between the Spokes and the Hub?
- Also your OnPrem should accept the traffic selector when Azure initiates a connection.
Cheers,
Kapil