Do you test it on only different log-in, same PC?
There is an issue that zoomed window can't show proper size of web viewer contents. Showing scroll bar is depend on how the site is written, so this can be the cause of your problem.
Is the site accessible public for our test?
It was tested on 3 different PCs, in Chrom, IE, and Firefox.
We will look to see if anything looks funny in the website code.
The site is a private site.