So I noticed a few runs recently scored pretty low in my HR zones, so today I dove into Garmin Connect for my 945 to check my HR zones and despite still having zones determined by "% of LTT" it had my HR zones all screwed up. Max HR was listed as 206 (185 previously) and thus it had my "easy" zone calculated as exceeding LTT (166).
I went back a few days to see when this change must've occurred, and it looks like between Sunday and Tuesday is when the HR zones were sent out of whack. Nothing has changed on my end to cause this, I haven't changed FW versions for example, so I have no idea what might have happened.
Just an FYI to other users, you may want to double check your HR zones in your app before it screws up your training readiness scores (not sure if it will but who knows what else might be affected).