There are a few reasons why your Mill may run even when you didn’t add new scraps.
Your Mill was just unboxed and paired
That is expected behavior - the Mill always runs a cycle the first day it's been unpacked. After that, it runs only when an estimated 0.22 lbs (for Mill 1st gen.) or 0.44 lbs (for Mill Plus) of food scraps have been added.
Your Mill may be making up for lost time
If your Mill’s lid wasn’t fully closed the night before, it may have skipped a Dry & Grind cycle. The next time you open & close the lid, and it engages correctly, your Mill will automatically go into a Dry & Grind cycle to make up for lost time the night before.
Your Mill mistakenly thinks you added some scraps
On Mill Plus and Mill 1st gen. if you set something on top of the device, the Mill’s weight sensors may think you added scraps. The weight system can also get out of sorts if the Mill gets bumped, or if the pedal or lid are messed with. For Mill Plus & Mill 1st gen., learn more about how to reset your Mill’s scale here. Mill Essential devices will run if the lid was opened after the last cycle ended.
Your Mill lost power or your bucket was removed and replaced
If your Mill loses power or your bucket was removed and replaced, it may run to make sure anything that was added in that time gets a Dry & Grind cycle.