"Limit to designated sites" and "Always Open This Site in..." conflict (plus infinite loop)

[umbralOptimatum]

• Multi-Account Containers Version: 8.0.7
• Operating System + Version: OS X 10.14.6
• Firefox Version: 100.0
• Other installed Add-ons + Version + Enabled/Disabled-Status:

Add-ons Search Detection extension 2.0.0 true [email protected] Amazon.com extension 1.3 true [email protected] Bing extension 1.3 true [email protected] Bypass Paywalls Clean extension 2.6.8.0 true {d133e097-46d9-4ecc-9903-fa6a722a6e0e} Decentraleyes extension 2.0.17 true jid1-BoFifL9Vbdl2zQ@jetpack Don't Accept image/webp extension 0.8.2 true [email protected] Don't track me Google extension 4.26 true [email protected] DuckDuckGo extension 1.1 true [email protected] DuckDuckGo Privacy Essentials extension 2022.4.26 true jid1-ZAdIEUB7XOzOJw@jetpack eBay extension 1.3 true [email protected] EPUBReader extension 2.0.13 true {5384767E-00D9-40E9-B72F-9CC39D655D6F} Firefox Multi-Account Containers extension 8.0.7 true @testpilot-containers Google extension 1.2 true [email protected] Privacy Badger extension 2021.11.23.1 true jid1-MnnxcxisBPnSXQ@jetpack Search Filter extension 2.1.13 true {fd12b446-5555-428a-9a2f-a07573b53748} Stylus extension 1.5.21 true {7a7a4a92-a2a0-41d1-9fd7-1e92480d612d} uBlock Origin extension 1.42.4 true [email protected] Wayback Machine extension 3.1 true [email protected] Wikipedia (en) extension 1.1 true [email protected]

Actual behavior

I'm trying to make a Banking container such that a) it's limited to the sites I choose and b) those sites will only open in the container. One of the sites redirects through multiple subdomains while logging in. I've added them all to the designated sites list as best I can tell. I've set at least some to only open in the banking container, though I can't figure out where to check this. But when I try to log in from inside the container, Firefox opens a new tab asking whether to continue in the current container or to open the site in the Always Open In container. Even though the site is already in said container.

Both options just lead to attempting to load the mid-login page in the new tab, immediately opening yet another tab to ask the same question. If "Remember my decision for this site" is checked, this leads to constantly opening new tabs until the window is closed. Turning off "Limit to designated sites" for the container prevents this from happening and I can log in without issue.

Expected behavior

If a page is set to always open in a specific container, and I try to open the page while in said container, it should simply open in that container without complaint.

Also we should be able to set the behavior for entire sites at once to avoid ending up with weird inconsistencies between subdomains, but that's the domain of existing issues (#473 etc).

Steps to reproduce

Since this involves a financial site I'm hesitant to give steps specific to that account system, but something like

1. Set container to "Limit to designated sites"
2. Set site domains to always open in the container
3. Try to log in
4. Unlimited tabs (memory limits may apply)