Hello Zeeshan, my thoughts are that it does not make a difference whether vlan is created on primary vpc member or secondary vpc member, whichever you choose to be vtp server, just make change on there, and it should be normal.
Ensure to add vlan to vPC-Peer link.
Only thing to bare in mind is the STP priority for the VLANs must be the same for both VPC members.
Hope it helps.
Bilal
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