I am having nearly the same exact issue with J1 1.7 and Gavick Boutique template.
Basically with system cache enabled (and gk_cache enabled and loaded first) there are issues with the module widths.
Originally the issue on my site (
www.design3.com) was with the gkContent width %. I tried @AntonellaCu solution which did seem to fix this, however it also messed with some of the CSS on the site, adding bullets in ul elements, etc.. I removed the code from cache.php, cleared the cache and miraculously the gkContent is acting appropriately -- however -- now it is #gkHeader1 that is doing the same thing! (caching the width of some pages and applying it to all).
The issue can be viewed by visiting
http://www.design3.com/governmentYou'll see that the top banner1 position image is truncated to 70% width (which is how it is set in template parameters and displayed on homepage banner).
The other thing that I didn't realize until reading this thread is that it DOES act properly once logged in as Will mentions.
If you create a free account and visit the same link above the header image will properly span 100% page width again... odd.
I assume this is a bug in gk_cache. Very interested in a solution as our servers are getting overloaded with processes and we need to be able to cache properly.
Thanks!
Case