TMG SP2 resets HTTP compression content types to default selection

A customised HTTP compression configuration will have the content types reset to the default selection.  The option to "Compress all content types except selected" and "Compress the selected content types only" will not be changed.  So if you have "Compress all content types except selected" chosen your configuration will essentially be inverted and then some.

Since the default content types cannot be altered, a custom content type is the only way to get granular control.  If for instance you would like to compress all image types except .gif (which normally increase in size slightly with compression) you don't have a choice but to create a custom images content type where you add all the default image types but leave out .gif.

Here is the default TMG compression configuration

Here is a customised compression configuration

Here is the customized compression configuration post SP2 install

Even if the TMG environment has not been customized prior to the SP2 installtion it might just be a good idea to check this after the install.