"When i ingest on the 2nd day the photos from the previous ingest are still there which is very confusing."
When you say the photos "are still there" do you mean in the place where you ingest your files? Did you move them? If you did not move them, then yes they would still be there in that same folder.
The Ingest process copies files from your memory card to a folder on your computer. If you come back and ingest more files later, Photo Mechanic will put them in the same place (depending on your settings) and will open up that folder and show all the files in that folder.
When you Ingest, there is the option to use the "global" Metadata Pad or a "local" pad
The Global pad will remember the last keywords that you used no matter where in the process that you open it. The Local pad will only use the keywords on that Ingest. If you use the (Global) Stationary pad later on during a Move process, the keywords you use from the Local pad will not be there.
Note: you can use the "lightning bolt" snapshot button (lower left of the Pad) to save your Metadata Pad settings, including keywords, to use later on, no matter if you are using Global or Local.