fastlane (probably?) dosen't know about "en-US/en-US"
https://f-droid.org/en/docs/All_About_Descriptions_Graphics_and_Screenshots/#fastlane-structure
It should be in
metadata/<locale>/
not in
metadata/en-US/en-US/
Edited by Clearedd
https://f-droid.org/en/docs/All_About_Descriptions_Graphics_and_Screenshots/#fastlane-structure
It should be in
metadata/<locale>/
not in
metadata/en-US/en-US/