This is the nature of Freeform, this is how it is meant to work
If you have the sync tracks song setting enabled and set to either Start & Length or just Length, this will likely have the sync you are looking for
If you have updated to 5.2.1 (now on WiFi), you can now import tracks into a quantized or autoquantized song making the synchronization even easier and makes it possible to use the Aeros with the BeatBuddy synced while also using backing tracks.
If you have any more issues please let @DanielSingularSound help you out!