If you use Gedmo Translatable you have an unmapped field mostly called "locale". According to the documentation:
Used locale to override Translation listener`s locale this is not a
mapped field of entity metadata, just a simple property
In Skipper you can write the locale field in the gedmo config - but as it is not a mapped field its get removed. you have to add the annotation by yourself everytime you export.
Please allow using an unmapped field in this case - or even better allow to add fields which can be marked as "unmapped" so they not getting the @ORM annoation.