In the VCF environment, it is observed that vCenter Servers display two NSX Manager plugins (server extensions) instead of one, while other vCenters in the same environment show only a single plugin.
VMware vCenter Server 9.x
This behavior occurs when a vCenter Server is associated with both a local NSX Manager and a Global NSX Manager (NSX Federation). Each manager registers its own plugin, resulting in two distinct NSX Manager extensions appearing within the vCenter interface.
This is a expected behavior based on your environment configuration and is considered cosmetic.