Since
@Hit_Factor posted a while back about his successful downgrade from a freescan beta version, I also did it. I took mine back to the version it was at before I ever installed either freescan beta as I still had copies of all my original PPS files that I never let it convert to the freescan version of PPS. I then tested everything I could think of but found zero problems.
After that downgrade, I installed (upgraded) to the official regular 1.3 version of firmware along with its recommended PPS version. Again, I found zero issues and my G5 has been working just fine. The DMR upgrade and model change I did for free when it was released still works fine as well.
I tried testing about everything I could think of after backing out of the freescan beta but never found any problems.
There very well could be hidden issues not found or reported yet but that's the risk we took for those of us that did back out of the freescan beta.
The warning from Unication may be just that, a warning to not downgrade as they have never really tested doing such and don't want to be liable if someone does and it breaks their G series pager from working as a pager.