I had a very similar bug in some software I wrote and used to perform in a band. The upshot was that everything worked fine at soundcheck; 6 hours later, the te

I had a very similar bug in some software I wrote and used to perform in a band. The upshot was that everything worked fine at soundcheck; 6 hours later, the tempos were off by about 8%, and varied pseudo-randomly during each song. The fix was to switch from float (24 bits precision) to a long int (32 bits), and to reset all the relevant vars between songs. Fun times!