Hi. I've a Garmin Forerunner 245 Music for 2 years and it continues to be a great device, overall for battery life and the charge speed.
In latest weeks I check a strange behavior of the battery.
Today I run for 1h 40m starting with 92% of battery.
At the end of my run the battery was at 68%: it seems so good.
Now, after near 2 hours from the end of my run, without any charing (only a shower and a good breakfast) it's at 71%.
IT'S INCREDIBLE