So I joined the Xbox Insider Program and downloaded the Better together beta.
At first it installed 1.2.0.20 and it ran just fine. The I found out it had an update pending and so i installed it. It installed 1.2.0.29 and wont updater any further.

So I did the same on Win 10 and it installed 1.2.0.31.

I have left the insider program
deleted the minecraft beta
rejoined the insider program
reinstalled the minecraft beta
even I uninstalled minecraft xbox one edition

i spent a full 4 hours working on this issue, i even called Microsoft support.
Microsoft support says "we do not support any betas"

I am currently trying to console factory reset. And i will try to get everything running again.

Edit: Update: console factory reset does not fully update
Edit: Update: https://feedback.minecraft.net/knowledgebase/articles/1807114-minecraft-win-10-android-beta-1-2-build-9 "References Xbox"