We deployed an update tonight that should rectify this, and events in IE8 should fire as normal. Also, Tweet and Follow Buttons counts in IE8 should also now display as expected. Please let us know if you run into any further issues.
Also, thanks to @niekkouwenberg who sent me a test case based on his site, and helped me verify the fix this evening. Always much appreciated to find people helping out at all times of day and night.
Ben