This is the first time I saw that issue, and I was the one triaging the regressions right before the 1.46 release. I think what went wrong there is the issue didn't have the "regression-from-stable-to-beta" (or well, any regression- label), so the release team didn't know it was actually a regression. The fact it was reported on an old issue didn't help either.
The best way to ensure the release team knows about a regression is to apply the "regression-from-stable-to-beta" label, and if that doesn't get attention ping the person driving the release (either me or @Mark_Simulacrum, depending on the release). That's not really easy though, as you need to either have access to the repo (to apply the regression label) or know who to ping.
I'm not sure how to make the process more streamlined though, any suggestion?