TFTP server is sitting in subnet which can reach via global routing table and your network devices is configured OOB with vrf routing.
You have no other ways to copy your files to your device except from TFTP server.
What will you do then? 😊
Leaking vrf to global routing or vice versa?
The answer is ...
ip tftp source-interface (Your OOB interface IP)
Have a good day.
(Be knowledgeable, pass it on then)