Rouchele ...
This ever was an indication for myself, and it denotes the more or less special situation that when a track (part) has played, at that exact moment the buffer with samples has ran empty. This normally is quite some coincidence. But what I now see (and think of for the first time), is that in a case like yours -playing with 3 samples of latency- chance will be 1:3 to let this happen, really.
But during the writing of this, it suddenly also springs to my mind that "debug code" like this - ever made for checking stuff at buffer boundary levels and which would happen at a relative LARGE amount of samples - is now performed once per 3 samples as in your case, or anyway much more than ever thought of when the code was created. This now obviously will lead to taking out that code, that by itself almost definitely leading to again a lower possible latency.
Your upside down nose is always good for something ...
Peter