Why doesn't TMG (former ISA) skip gzip for pages with javascript headers?

Question

JavaScript

Please, prompt:
There is iis, behind it there is TMG.
I decided to make optimization and set up gzip compression.
Everything works on LAN, either on iis express or just on iis.
But on an external server it works partially, for text/html and text/css everything is fine, but for text/javascript, application/javascript and application/x-javascript gzip is cut and reaches users without compression. And if you go to the server and run the site as a local one, then everything is fine too. With a 99% probability, the problem is in TMG, but there all permissions for serving content with compression are configured according to the mask of the text/*, application/* headers. Tried disabling the "Disable the Compression Filter and Caching Compressed Content Filter" modules altogether. Where else can ISA cut compression for javascript?