SAP WM Group already processed

Guys. I looked up online for possible answers but no success

Problem: An open TR  (total qty 50 )is assigned to a group from which there is a Transfer Order for 15 (already picked).

Now if I try to create TO for remaining TR quantity (35) via LT04. I get this warning message;

TR XXXXX is already assigned to a group XX XXXX.

If I ignore this message and proceed with TO creation. it creates TO without Group number.

Is there any way to create TO with the group number? Is it standard SAP behavior? Is there any notes or fix or config change?

PS: I believe since the group is already processed so it doesnt allocate it to future TO