The red color indicates that the songs have different metadata. If you check the selection Box and confirm with okay all the selectet Songs will get the same Information of metadata in that field. Its a "merge" function.
Samsung Galaxy Tab S7 FE Android 12
Samsung Note Pro 12.2 LineageOS 14.1
Huawei Media Pad M3 lite Android 7
Samsung Note Pro 12.2 LineageOS 14.1
Huawei Media Pad M3 lite Android 7