it seems that we cannot open two different Orchestrator Tenants in separate tabs, both under same Organization. If you open Tenant A, then Tenant B, the url of the first tab will still be Tenant A, but the Orchestrator will actually be from Tenant B.
It’s because both Tenants has same URL. You can open both Tenants in different browsers or open one Tenant in normal mode and other one in Incognito mode.