This is odd behavior, but please note that even if you were able to supply a workbook, it's likely that most of us here on the forum wouldn't be able to recreate as we've long since moved on past release 9.1 (circa 3 years ago).
Can you look at these?
1. Upgrade to a more recent release (i.e. 10.5 or 2018.2)
2. Add a tag onto the end of your URL to test both client side rendering and server side rendering. The syntax goes something like ?:render=false , but refer to this link for more details. About Client-Side Rendering
3. What browser are you using? Does it happen with every browser type?