I run Windows XP and see this problem in the Admin Console with any of Explorer, Firefox or Chrome set as preferred browser.
Immediately after logging on to the Admin Console, under the main tab, if I select a keypadlink sub-switch or a remote link 2 switch from the ISY list, the first time the name in the main screen displays correctly.
After that, for an INSTEON device in the ISY list, the first character of the name is overwritten by the last character in the name.
If I select a device under a scene, the displays in the Current State, On Level and Ramp Rate are corrupted, usually with f and % characters. If the state of the device changes, the display corruption sometimes changes to a different corruption or displays correctly.
This problem doesn't show up when I use Safari, Explorer of Firefox on our MAC.