When importing Monolingual XML and defining Locked elements & attributes, the segments in Editors are in source but not in target.
There is an option to check that you want to copy source to target for elements or attributes that were imported through Locked elements & attributes field.
Linguists have more visual context to see the locked segments.
Do not import those elements or attributes since they don't need to be translated (do not use Locked elements & attributes)
Or after the open segments are translated, select locked segments, unlock them, copy source to target and confirm them.