We noticed a strange behavior in Revit 2022.
After entering Edit Assembly mode and initiating the Rebar command, the green contextual tab is missing.
Without entering Edit Assembly mode, the contextual tab displays as expected.
In Revit 2021 and prior, the contextual tab was available after entering Edit Assembly mode. So for me this feels like a bug. Though I'd love to see the opinion of @ovidiu_paunescu