[ovirt-users] Unable to start VM on host with OVS networking

I have a production ovirt setup that's gone through multiple updates over the years. At some point when 4.0 or 4.1 came out, I switched from legacy networking to OVS, and everything worked perfectly until I upgraded to 4.2. Since I upgraded to 4.2, I've been getting messages that the networks were all out of sync, but everything continued working properly. Today I tracked down the network sync problem, fixed it on one of my three hosts, and then attempted to start a VM on the host. It refused to start with the error message: "Unable to add bridge ovirtmgmt port vnet0: Operation not supported". From what I can tell, the xml being generated is still for the old legacy network. I completely reinstalled the node, using the latest 4.2.3 node ISO image, and it still doesn't work. In the cluster, the switch type is "OVS (Experimental)" (and this option can't be changed, apparently), the compatibility version is 4.2, the firewall type is firewalld and there's no "Default Network Provider". I suspect that my upgrades have somehow left my system in half OVS/half legacy mode, but I'm not sure how to move it all the way to OVS mode and I don't want to mess with the other two hosts until I'm sure I've got it figured out. My (compressed) vdsm.log is at https://www.lesbg.com/jdieter/vdsm.log.xz and my (compressed) supervdsm.log is at https://www.lesbg.com/jdieter/supervdsm.log.xz. If anyone could point me in the right direction to get this fixed, I'd sure appreciate it. Jonathan