Hi Jeremy-
If you’re only split testing a few pages, I recommend adding them to Never cache the following pages in your Performance > Page Cache menu.
If that’s not going to work (i.e. you’re testing a large number of pages) can you share a little more information?
Which caching method are you using for your Page Cache? “Disk – Enhanced” does not support caching redirects, but should be bypassing redirects as if no caching were enabled.
Also, do you have the option enabled to Cache URI’s with query string variables in your Performance > Page Cache menu? If so, try disabling that option.