Hello Ivan,
what do you mean by HU being stuck between EWM and 2171?
Does inbound delivery exist in EWM?
If so, it depends whether your putaway activity has not started yet. You need to reject the inbound delivery document in PRDI in EWM and this is possible only when putaway not started.
Rejection makes the ECC inbound delivery quantity zero and closes the document.
Regards,
Petr