The reason for this inconsistency is because the preview runs at a different engine depth than the one in the analysis board. The analysis board one is probably a slightly longer review and therefore, more accurate.
The review “percentage” is called CAPS (Computer Aggregated Precision Score) and you can hear me discuss this here:
https://youtu.be/fXOnBJ4KX1U?si=gEqe1dv-9pktBMJC
Sometimes when I look at the preview for game review (The thing you see at the end of a game telling you how many of 3 different types of moves you made) it's different from the full game review. Sometimes, a game'll say I played 3 or 4 great moves when in reality I only played 1 or 2.
For some reason, I only find it with great moves. Maybe around 30% of my recent games (with great moves) have incorrect previews, but it's really inconsistent and I don't see any patterns with it.