occasional crackling with ultrasonic, do you guys get it too?

[dissonance]

I often get crackling (almost always) in the first 10 seconds or so of an ultrasonic file, then it becomes silent for the rest, and then crackles for 10 seconds occasionaly (once or twice each playback of the file, often times in the same spots). Do you guys get this too? And is this ok? Did you guys get results from listening even with this momentary crackling?