174.00 and the most accurate analyses (to the best of my knowledge) give me 173.97 (true example),
So... By the end of a 5-minute song, the timing is "off" by ~50 milliseconds (1/20th of a second). Obviously, "No human musicians were harmed during the production of this music."
How does that "confuse" you? You can't hear the difference, can you? I don't know hat you are doing when "mixing", but I would
think if any time-alignment needs to be done, you'd be aligning beats & measures rather than worring about the exact BMP clock.
OK, I can think of a couple of possibilities other than a 0.017% clock error, which is certainly possible. Consumer soundcards can be off by a few percent. That's enough to cause pitch errors, and sync errors if you record on one device/soundcard while monitoring the backing track on device/another soundcard. (That assumes there was some actual "recording" somewhere along the line.)
The producer could have used a "humanize" mode that throws-in slight random timing-variations, or maybe a "groove" mode that makes some beats a little early, and other beats a little late.
Or maybe it was re-sampled, and there was an accumulation of teeny-tiny errors.