Hi TMG Admins!
Today ISA/TMG team has released Rollup 3 for TMG Update 1. This new rollup includes a number of hotfixes which solve some problems reported to Microsoft by customers.
Many of this issues are related to HTTPS inspection mechanism, so if you enabled HTTPS inspection (as you should ) on your TMG, it is definitly worth to take a look at the rollup.
As for prerequisites, you must have TMG Service Pack 1 and Software Update 1 installed on TMG machine.
For a complete list of what is been fixed: http://support.microsoft.com/kb/2498770