Page Details Property pane not showing metadata columns

Dean_Gross et al.
I recently had this problem too.  The solution I found was:

1. Navigate to the Page Library
2. Open the Library Settings (gear icon in top right of the page)
   1. If you are in modern view, you might need to click on the More Settings link to get to the Classic Admin view of the list/library settings
3. In the middle of the Settings page there should be a Contents Type section.  Open each content type and add the column you want to show up in the Details pane

Hopefully that helps.