Going way back, before SERVER-69168, nearly every test in jstests/core/timeseries was tagged with tenant_migration_incompatible, but new tests were sometimes not tagged the same way as existing tests for necessary exclusions (tenant migrations among others), and we would get intermittent, hard-to-reproduce failures.It's not 100% clear to me why we initially had those tests marked as tenant migration incompatible, and it's possible it's not necessary any more. If you want to try kicking off a patch (or few) without the requires_timeseries exclusion for tenant migration passthroughs and see what breaks, that sounds reasonable to me. If it turns out there's a specific subset of tests that are currently incompatible, then we can just tag those tests instead of the blanket exclusion. (Similarly, we have several tests that aren't compatible with stepdowns, so those are tagged, and we're planning to move those to noPassthrough in a future ticket.) If it looks like a more general test compatibility problem (not limited to small set of tests), then that's worth investigating sooner rather than later.