Cloud Run PM here. Sorry for the inconvenience. This is an issue for which we have a fix, but the fix still needs to roll out (internal bug 154368323 for googlers reading, we're still evaluating the best rollout strategy). Until then, I'll add it to https://cloud.google.com/run/docs/issues.
I only say this half in jest: Google, please give this person a raise. I'm not sure I've ever seen a Google PM be this up front and straightforward with a future roadmap item, even in HN, where I more commonly see more direct communications by PMs or engineers from various companies.
While you're at it, if there is a way you can get the Google Identity Platform PM to let us know when some form of multi-factor auth besides SMS will be supported, that would be great!
I guess the main problem is the second part of the subOP comment:
>While you're at it, if there is a way you can get the Google Identity Platform PM to let us know when some form of multi-factor auth besides SMS will be supported, that would be great!
When they respond they get inundated with random requests and ailments that they have exactly zero control on.