Contacts not appearing in project explorer

For the two most recent projects I have created, the contacts did not initially appear in project explorer. I believe I created both of these projects in the same manner as prior projects.

The projects do appear as categories on the individual contact card.

When clicking on the project icon on the contact card and viewing the list of projects, the project does appear but initially there is not a check mark next to it.

In projects created earlier, the contacts appear and there is a check mark next to the project when the project icon is clicked.

For both of these projects, they appear twice in the list of categories in Outlook.

When I select the other project with the same name in the Outlook categories list, then the check mark appears next to the project name when the project icon is clicked on the contact card.  The cards also appear in project explorer.

In the Outlook category list, one project has "(not in Master Category List)" appended to the end of the name.  The other does not.

For the one does not, I could delete that category and the contact card stayed in project explorer and the check mark stayed next to the project when the project icon was clicked on the contact card.  For the one with "(not in Master Category List)" Outlook does not give me an option to delete it.

The outlook version is 2010 and I am running windows 7 64 bit.

Thanks for any help you can give me to avoid this situation for future projects.