version 2017.1 Win 64
For the moment you could only check this thread:Re: Left property should be a pixel value! Troubles with Adobe Muse.
For some reason the error disappeared after fixing several layout/design issues.
So I recommend to start with the master page and look out for some elements, that might flee the canvas at a certain width.
Do the same to your pages, step by step and try to fix as much as you can. Test.