Since 3.3 is still in beta, it’s quite possible that it’s a bug in the current version. I would try installing 3.2/stable and test a deployment of ubuntu to see if you have the same issue with your current setup. If that doesn’t work, see the reply I made to your other recent post.
https://discourse.maas.io/t/network-discovery/6506/2?u=ben-ihelputech
I would be suspicious that it’s your network config. My understanding is that MAAS needs to be able to see your IPMI interface and your PXE interface.