LTHR test value three different readings depending on which platform I view it on

I did the lactate threshold test and was told the result was 173bpm at 5:30/km. This result is now displayed in the VO2 max glance area of the watch.

On the Garmin Connect app on my phone (More | Performance Stats | Running Lactate Threshold) it says it's 163bpm, although with the same pace value.

At this link on the Connect website: https://connect.garmin.com/modern/report/49/running/last_four_weeks it says 163bpm again, this time with a pace of 5:31/km, but if I move the mouse over the red heart rate on the graph, it says 171bpm.

Which value am I supposed to be trusting? 173 seems the most realistic to me, if anything it seems a bit low, but I don't understand why the other platforms give different values. There isn't much point training at the threshold value if I'm actually 10bpm above.

Is it different for other people too?