Not accessible using Orca screen reader

I'm proxying this report for https://launchpad.net/~hartmans. For reasons that will become obvious in a moment, he's unable to file it himself.

"""
Hi. I'm trying to log in from the firefox-usr in Debian (78.6.0esr)
with the Orca screen reader for accessibility. I go to launchpad.net.
That's fine. I click the login/register link. I get to a screen where
the voice prompts are to type in my email and <email address hidden> is
pre-filled in. But it's like I'm trapped in some modal dialogue focus or something and I can't navigate anywhere to hit next or submit or
anything. I cannot even navigate the page enough to figure out what I'm supposed to do next.

I don't use launchpad that often, so I don't know when things changed.
In general, Launchpad accessibility has been fine.

Normally, I'd file a bug.
But I suspect that it would require me to log in to file a bug:-)
So I'm hoping that perhaps one of you could file a bug on my behalf.

I'm happy to provide whatever information would be useful to reproduce.
"""

After some email discussion, I've established a few additional facts. The page Sam gets stuck on is an SSO `/%(token)s/+decide` URL on login.launchpad.net. Sam was reasonably reluctant to provide a screencast of the process without being sure of the privacy of whatever else might be on his desktop, but he provided the result of printing that page to PDF; out of an abundance of caution I've taken the liberty of exporting that to PNG in order to erase a token that was visible in the page's URL. I can see what I think might be a little bit of the cookie consent dialog at the bottom of the page - is it perhaps possible that that might be interfering with screen readers?