Currently, the stamper discards one of its outputs if one side is blocked and the other is not. It only properly stalls when both outputs are blocked.
This breaks backpropagation for designs that require it, and it can also make it difficult to avoid discarding material.
I would like one or two toggles somewhere in the stamper that define whether to block on an output. Ideally it could be configured so that either or both outputs can toggle blocking, but I'd be happy with even just the main one.
Existing stampers in saves could be set to block on neither to match current behavior and not break existing builds.