Digital Micrometer | Model Engineer

I was given a Digital Micrometer as a gift. It arrived in a Wooden foam lined box. I used it yesterday to measure something having set it to zero by using the ratchet and pressing the reset button After finishing the measurement, I closed the jaws again using the ratchet and the display read 0.002mm That's NOT what I would expect! Am I doing something wrong? Or shall I dispose of the micrometer? I do NOT leave the little button cell installed when the instrument is NOT in use - just in case it leaks! Any suggestions or comments, please?