Publish Profile manually-provisioned results in "invalid credentials"

I haven't been able to have the action run whenever I've downloaded the publishing profile, then set that manually as a Github Action secret.

I've verified that I'm setting the secret with the same name as specified in the workflow file, and I'm directly copy/pasting the profile for the specified slot.

However have only had it work, when I authorize via portal, and let it create the workflow + secret in my Github repo.

Just wanted to check if anyone can successfully do this (manual setup, paste secret)?
Or is it PEBKAC and I need to re-verify my setup.
Thanks!