To me it sounds like a buffer that is not getting dumped (emptied) when Stop is hit.
I've seen plugins do this. Then when Play is hit the buffer unloads all at once .. and no other sign of a problem shows up with the plugin, so it can be deceiving.
Often it can be seen in a meter somewhere, if seen on the Tracks meter it helps narrow things down quickly.


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