This is a minor *Repeatable* glitch where the diplomacy demand window is pre-filled with some (last?) trade items. This only happens if you:
1: Go to diplomacy screen with any AI (You will get the exact same result with any AI)
2: Click "Declare war"
3: Click "NO" to cancel the war declaration. Then click on "DEMAND" to see the repeatable bug
and voilà! This bellow is what I believe should be seen instead of a pre-filled trade demand window
1: Go to diplomacy screen with any AI (You will get the exact same result with any AI)
Spoiler :

2: Click "Declare war"
Spoiler :

3: Click "NO" to cancel the war declaration. Then click on "DEMAND" to see the repeatable bug
Spoiler :

and voilà! This bellow is what I believe should be seen instead of a pre-filled trade demand window
Spoiler :
