I've been trying to figure out this mystery for a couple years now, maybe one of the Garmin reps that lurk here can figure it out or ask some internal Garmin developer who knows the undocumented "secret".
The top row is before the download, using the firstbeat metrics etc. on the watch with live broadcast from HRM-TRI to Fenix via ANT+
The bottom row is after the HRM-TRI download using the menu on the watch after it processes the data.
There is no way, in heck, that I use 2.0 effort anaerobic. That would be a tempo/workout level effort.
You can see it shifted around some seconds in the zones, nothing dramatic. 2.0 anaerobic would require MINUTES in Z5
So this has to be a bug in how it looks at the watch zone settings and the firstbeat metrics.
The question is: where is the Fenix getting the HR zones from to re-calculate? Can they be changed?
Because they clearly do not match what is set in any of the five or so user settings in Garmin Connect and on the watch.
Happens every single time, this is easily reproducible for any activity, running or cycling.
(what's also a bug is that the watch doesn't update the average load or recovery time for the newly perceived training/HR)
