So the problem is:
If order 1-4 are in tape library then no mount request is issued
and
if order 1-4 are not in library then mount request is issued
In a way it makes sense, however DP should find out that instead of Tape1 say Tape5 is in the device and use that...what's the allocation policy of the pools, strict or loose? If it is strict, then the behaviour is normal....for loose allocation, it is a bug I guess...