The issue was to do with some shapers we had on our BNG's to support the Chorus implementation of the UFB services.
They didn't work too well with UFF/Enable. This should be resolved for all UFF/Enable customers now.
If there are still issues please let us know, so we can make sure you are on the right profiles.
There doesn't seem to be a duplex issue that we can see. We got ONT's checked and we saw they were all auto-negging at 100/full as expected.