For a while I’ve been experiencing this annoying issue where horizontal bars would appear in my PDF Viewer built into Chrome.
It finally annoyed me enough to do a little research. The issue is discussed here.
While at the time of posting the problem still isn’t fixed, it finally became clear to me that the problem only occurs when the horizontal scroll is displayed.
Thus, a work around is to zoom out the PDF viewer enough to show the whole page, then the problem does not occur.