Comment 7 for bug 1818294

I don't think we yet know that one of the changes between 5.0-rc1 & 5.0-rc8 would fix this. It could be an issue with the backport, or a change in a different subsystem. But, as a test, I went ahead and backported the hns changes to a PPA:

https://launchpad.net/~dannf/+archive/ubuntu/xr320

If that build does fix the problem for you, then we can narrow down what the significant change(s) is. Of course, once you're able to test I suspect you'll also be able to collect the logs of the failing build, and that should give us more direct info.