In AudienceReport you are able to see if your cache-buster is implemented correctly, and if it is working.
Go to your project, and select the tab “Traffic Quality”. On the top of the page, you can select the tracking pixel for which you want check the cache-buster implementation. Simply select the given tracking point under “Traffic quality for (...)”.
After selecting the pixel, scroll down and you will find the cache-buster ratio.
If the cache-buster ratio is 100, the cache-buster for the pixel has been implemented correctly.