As I mentioned, it's likely a buffer emptying, sounds like it's a plugin buffer.
If you let it play through to the end it likely won't happen, as the buffers get played/emptied, but if you stop the song somewhere it will.
It may also be that the track itself doesn't contain enough empty space at the end for the plugin to finish emptying (delay and reverb type effects need additional track space or time to finish processing) ..

In this case adding a couple bars of silence at the end may bring joy.
Hard to say if it is RB itself or the plugin so far.
Either way they are not 'playing nice' together.

I do not work here, but the benefits are still awesome
Make your sound your own!