STABLE version -- 5.1.1130.129

[Admini]

Admini
Are you planning to restore the old behavior of multilogin tabs in the next release? Now the sessions are shared between the nested tabs. For example, if you want to test the same form on the site, you have to open even more tabs until you finally reach the clear one.

Do you mean that multilogin tabs with different dots have the same cookies?
Does enabling this option resolve the issue?
"Clear browsing data automatically after closing multilogin tabs" in chrome://settings/privacy