I am currently suffering from this bug: https://bugzilla.redhat.com/show_bug.cgi?id=548520

The listed work-around is to enable the updates-testing repo and update NetworkManager* until the fixed package makes it into the updates repo.

I have always been worried about using updates-testing due to problems I ran into in the past from my own mismangement of yum repositories and having conflictions when trying to apply my next batch of updates.

What is the best procedure to follow when needing to apply a work around from updates-testing? What I am worried about are inconsistancies that may break future updates by enabling this repo and installing software from it. Do I simply enable the repo, update the necessary packages, then disable the repo? If I do this will the next NetworkManager* updates know to pull the updated packages from the 'updates repo' rather than looking for an update from the 'update-testing repo'?

Enable the repo, update the desired packages then disable the repo again.

Future updates will be fine.

Updates work off of your OS version not where the last update came from :

Name=Fedora $releasever $basearch

Make sure you disable the repo straight away though.
If the system runs a general update while the repo is enabled, then you may get problems.

The underlying issue is that Fedora is RH's R & D distro and as such is 'bleeding edge'. This sort of thing is likely to happen.
If you want the absolute latest whatever, then that's fine, but you'll have to get used to it.
If you want an RH like system, but more stable, get Centos (free version of RHEL).
I did, because I got fed up with Fedora for the above reasons ...

there's bleeding edge and there's updates-testing on bleeding edge ...
That's while the sword is still going in !

I've not found fedora to be too unstable in the last releases I've tried (9, 12).
YMMV as they say.