I've found all of the same problems in compatibility with the Ubiquity stuff. It's kind of like Black Magic video do-dads: they work great as long as they're only talking to other BMD stuff.
Instead of injectors, for not much more money I've just been buying Netgear GS110TP switches. They ship configured with everything Dante compatible for Dante only networks. I would want something a little more sophisticated if I was doing a bunch of multicast on a mixed network, but if it's just a Dante network powering Avio/Aphenol/Rapco devices, this thing works great. As a bonus, it will also power their even small GS108T-V2. If you power the 108 with a wall wart it gives you redundant power to the smaller switch, although the failover isn't graceful at all. With the Netgear stuff, make sure you stick with the Managed Pro line, the Manged Plus line is no bueno for Dante.
Amazon link:
http://a.co/d/0iewKEQthomas d.