Ok Chris, i took a quick peak at this.
I did what I assume you did, which, again assuming, you did dnxHD not dnxHR?
I created dnxhd 720 8 bit media, exported an ALE out of Resolve.
Brought that media into Avid via link, and tried to import the ALE…got the same result as you, an error. I then exported an ALE out of Avid to see what was different. The ALE in Resolve does say that the media is (in my case) 4k, not 720, which makes sense, as the ALE is based on source material, not what you are about to output.
I’m not sure that is the issue however. I think it is the DNX HD. When you get 1080 to work, are you doing DNXhd or DNXhr? I ask, because the other item i see in the ALE from Avid is the clip name has a .mxf extension on it, but the ALE from Resolve doesn’t. Once I changed this in notepad ++ the ALE merged inside Avid.
I did try changing a couple of other items along the way in Notepad ++, and none of them solved the problem until i lost the .mxf extension in the name column. It is possible it worked because of a combo of things, but i’m guessing it was the .mxf extension.
Give that a try and see if it works.
Glenn