Your project is in English (United States), but somehow the root English language attribute was applied to many topics throughout the project. This is evident from a small flag icon at the top of those topics in the XML Editor.
You want to remove this language attribute so that all topics are using English (United States), set at the project level.
Example Set the fields like this:
- Find
-
Attribute - xml:lang
- en
-
- Replace/Action
-
Remove Attribute - xml:lang
-
- Find in
- (whole project)
- File types
- Topics
Click Replace All.