I’ve had no similar symptoms but would like to replace the CR2032 as preventive maintenance. I bought my M1 in September of 2015 and it’s performed well since.

Page 6 of the Installation Manual I have says, “Lithium 3V “Clock” battery, Varta #CR2032 located in upper left corner behind cover. Battery has a life expectancy of approx. 10 years. Replace ONLY with exact model available at most electronics and camera retailers.” Searching online for Varta finds that the CR2032 batteries are now made in China vs. in Germany. What brand have other owners used? From what source? Thanks!