It's very unlikely to be a glitch with the ADC in the studio. Firstly, ADC glitches are rare and secondly, it would be very surprising if all the musicians, engineers and producer missed the glitch (or decided not to fix it) during all the phases of recording, editing, mixing and mastering. Having said this, I have been "very surprised" in the past, not so much by missed ADC glitches but another cause of digital clicks; I recall many years ago analysing "The Streets" first big album hit with a class of students and was more than a little surprised to hear several "editing clicks", a real rookie error and to this day I don't understand how they could have been missed or not fixed. BTW, an "editing click" is one of those "different potential causes", it occurs when an audio file is cut at a non-zero crossing point and the speaker/HP driver thereby being asked to make an impossible instantaneous movement, which results in a "click". It's the same basic problem that some CD players suffered from, using FF or starting playback halfway through a waveform and effectively asking the speaker to move from zero amplitude to a significantly different amplitude instantaneously. The solution is simple, a very short (couple of milli-secs or so) inaudible "fade-in" which should always be applied when editing an audio file (except if it's edited at a zero-crossing point anyway) or in the case of a CD or any other digital audio player, implementing a "fade-in" every time Play, FF, RW or Stop is selected (which has been standard for many years).
G