RE: One account can see "post" in Invoice Journal, but cannot see "post" in Vendor payment journal.
Hi JustZM,
At a high level, security diagnostics on the form will provide which role/ duties/ privileges are used on the form. If you want to identify which specific privilege, follow steps per below:
1. Go to form and then right click on 'Post' field and click Form information > form name. it open up another window. scroll all the way to the end. On administration tab, you will find the menu item name. Screenshot below for the invoice journal form.

Now go to visual studio (provided you have access) and select this menu item and right click > find references. then in the references window scroll down to view privileges

Double click on it and it will show you the privilege. Do know that the same privilege is going to contain other menu items as well.
You can repeat these steps for finding the menu item for any of the journals.
See below so you can get an idea of how many such menu items exists:

If you don't have access to VS, once you know the menu item name, start with roles identified from security diagnostics and then review the privilege to determine which privilege contains the menu item.
Thanks,
Satish Panwar
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