10.3.3
For a vapp direct network, if the vm nic is modified to change pool type from POOL to MANUAL, while keeping the same ip address, the modifications are not saved. This behavior was changed in later versions.(Please check Resolution)
The fix for this issue is included in newer releases of VMware Cloud Director.
Review the VMware Cloud Director Release Notes for versions 10.4 or later to confirm the resolution of this specific API behavior.