I had the same problem. I got it to fix. Don't know if this will help, but here's how it fixed for me:
I was using duck duck go browser. I am running windows 11. I switched the default browser to edge (it had been duck duck go), then I rebooted my computer. It updated a lot of files during reboot. Then I opened turbotax and imported vanguard tax docs again and it worked.
GLTA
p.s. rethinking turbotax next year. They were slow to fix or anticipate conflict.
