Cannot create a collective HU with unknown content

Hello

My client has cases where there's no ASN from the vendor. So there's a need to receive HUs with unknown content during GR. When I tried to build this scenario in the system, I'm facing the below error. (Error occured during creation of HUs for GR with unknown content. Message no. /SCWM/UI_GR082)

Please throw some light on this.

Upon debugging, I found this. Does it mean collective HU cant be created if POSC is used?