The problem with time is that the earth isn't rotating at a constant rate. So it doesn't really matter what measurement you use, it will always be inaccurate (at least any system related to the rotation of the earth). But 8 minutes is way too long, at the most I'd expect a few seconds of difference if it were caused by a leap second issue.
I would suggest that one of the clocks isn't synced properly. Which one is unknown, both are feasible to be out by that amount of time. There are a few timezones that work in 0.25 and 0.5 hour blocks, but there doesn't appear to be that many. At 8 minutes off, that doesn't sound to be a correction for a timezone or DST or anything like that, it just sounds to be a system clock that's off.
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