Getting rid of contact history (?) in drop down on a project plan



I'm using the project template pack as a start, but frustratingly the "template contacts" still appear as history in the contact column, as well as some contacts I added then removed:

None of these are in my Account> My Smartsheet Contacts... list. So why does it not go away? Very irritating. The whole column is cleared of any values.

A 2016 post suggested a little "x" next to the contacts for easy clearing of the histoy (presume that's why they''re there). Would've been nice, but anyway.

How do I get rid of this?