Hi Jürgen,
I've exactly the same problem. When QUANT is created by pchysical inventory the field LQUA-LETYP is not filled.
The storage type is not SU active.
But, the SUT missing in LQUA is generating the message "Enter SU type" when executing L_TO_CREATE_TR to a storage type with SU active.
I've already checked the customizing for Inventory and for move types 711 and 712. I couldn't find nothing relevant.
Tks in advance.