I'm not particularly familiar with this project yet, but am told that online diagrams with links are not displaying properly in newer browsers because the version of Visio that was used is obsolete. Various elements of the charts are not displaying, such as the text!!! I'll plan to take a closer look at this project later (am busy with another now) but hoped to throw this out there for any thoughts.
Have you seen this before and are there ways of addressing the problem without updating Visio? The expense isn't viable.