Im running the latest stable firmware but had this issue for a few releases over the last few months (NEVER before 2024 releases).
In any sort of activity, very often (but not 100%) of the time it takes 5-10 minutes before it locks onto my HR and begins tracking it. Note this is both with a chest strap (Polar H10) and the wrist based.
The HR starts, reads low then suddenly jumps to correct.
This example is yesterday using a Polar H10 (wet contacts, new battery, displays OK on the polar and Strava app from the start).
20 mins later i changed to another machine and went back to the wrist based HR and got the same:
Im seeing this a lot but not all the time. Its always 5-10 mins before locking using chest or wrist HR. In additional to chest HR sometimes drops low and stops responding 45-50 mins into a run.
I never saw this behaviour prior to the last few firmware updates.
Any idea whats going wrong here?