exporting translation file the value is empty (branch stable server)

in branch stable server when we do the export translation,

for the fields which are translated from the Client , the translation (value) is not coming in csv file.

it is happening because when user translate the fields or anything from the client side
the source is now coming and even it is not writing the value for Source (src) field.

and when it is fetching records to save in csv file . it is passing the source in the _get_source function . as the src is blank in database the it is not getting the value.