So I recorded 30min of the stadium challenge timer and put an onscreen timer for comparison. Then I grabbed one of jtb's archive challenge videos and put a timer on that too. On both the real time tracker was faster than the ingame timer on both versions of ngb (ntsc and pal).
*Edit: Also did the timer test for original xbox on MN archive challenge. Timer starts at 2800.
Image of the timers in question
Spoiler:
Was this an issue that was posted about a long time ago in Iberian's realm?
xbox one x
xbox 360
original xbox