You should exclude your parameter from the chash calculation. Its can be done in the install tool. In the "all configuration" section search for "cHashExcludedParameters". Every variable listed here will be ignored when building the chash for the page. By default you should have your language parameter listed here for example: L
Now all you need to do is to add your parameter to the list. Given that your parameter is namend "utm_campaign", it should look like this: L, utm_campaign
You can add additional parameters as comma seperated list: L, utm_campaign, foo, bar
Make sure to clear you caches after the change.