Gossen Color Meter Battery Life

Does anyone have experience with the Gossen Colormaster (aka ColorPro) 3F color meter’s battery life? I have one that is less than one year old. Several times when I have used it after an interval of a month or three, the battery is completely dead. It has a two-stage, bad-battery display warning which I have never seen; the battery evidently being so dead even the display is dead. I keep it in its case in my camera case where it is put more-or-less randomly so it seems unlikely that the button is being pressed and held by something else in the case. I am beginning to conclude that it is broken in some way that drains the battery. Any thoughts?

My first Gossen color meter 3F drained the battery, my repaired color meter (complete new printed circuit) drained the battery, so it looks quit normal to me. After use and not using it for a while I remove the battery. I don't like it but I can live with it.