Incase anyone else runs into this problem, I found a workaround form the Adobe forum. Just tested it and works perfectly!
Original post – https://forums.adobe.com/thread/2406907
1. In the project panel, select the clip/s that have been interpreted & need proxies to match.
2, Right-click, “Proxies/create proxies” which will cause AME to launch.
3. IMMEDIATELY switch to AME and stop the processing of that first proxy file.
4. Right-click the file, select “Reset”.
5. Select that and any other files you may have sent along, right-click, “Modify/Interpret” and set to the same time-base as the original media’s interpreted setting used on your timeline.
6. Start the processing.
7. When complete, all but that first file you stopped & reset will show as “attached”, you’ll need to attach that first file.
8. Select that file that isn’t attached, right-click, and ‘attach proxies’.
9. In the dialog box that pops up, navigate to the location for your proxies, select the proper file, and click “attach”.