'Maintain Library" seems to reproess entire library every day

Even though I have the 'only update files with missing information' box checked it looks like my entire library is processed every day. Is it looking for subtitles even on files that don't have them? I've got a mix of MP4 with & without subs. So, everyday my machine is churning for hours every day in the 'Getting text metadata & artwork' process. I've unchecked the box referring to subs to see if it changes tomorrow but I figured I'd post here to see what's up.

If you are maintaining your complete Mezzmo library, then Mezzmo will analyze each file and check for the information you have specified (i.e. "Update media information", "Update subtitles", "Update artwork"). The "Only update files with missing information" checkbox means that Mezzmo will only update empty fields for files in your Mezzmo library.