Book Order with Cancelled Line / Qty Cancelled issue

I imported a Sales Order with two lines via Order Import  (It is stil in Entered status. )

Next from front end cancelled Line#2 by providing a cancell reason and clicked ok.

The Quantity became Zero (which is fine) but then Qty Cancelled  field is not showing the qty cancelled. ???

Now when I try to Book the sales order it shows a message that  a Line has Zero qty and stays in Entered status. ???   

is this standard OM functionality ?

Once the cancelled line is deleted then it allows to Book the SO.  (but due to business reasons I can't just delete the line as its imported via Order Import from legacy system and so we are trying to cancel instead of Deleting lines for audit purposes).