K26885505: FAST for Common Partition BIG-IP LTM 16.1.0
AS3 only writes to the Common partition when you specifically use /Common/Shared. Otherwise, AS3 does not write to the Common partition for LTM configurations to ensure there is no impact to an existing device configuration where both AS3 and legacy configuration methods are being used.
While use of separate partitions may be new behavior for some users, F5 has designed AS3 in this manner in order to deliver the safest possible deployment mechanism on BIG-IP.
The use of separate partitions also prevents possible naming collisions and maintains a logical object hierarchy that allows AS3 to deliver stable transactions (atomicity) and idempotency.