I cannot possibly know what your issue is - so I am guessing your issue is hardware related.
What I do know is that I tested the three plasma ISO before release - and they worked as expected on bare metal - installing and everything else.
The issue may be caused by bad download - you could use the manjaro-iso-downloader from the official repo as it will verify the iso after download.
Or you could use the python script provided [root tip] [Utility Script] Using python to download and verify a Manjaro ISO