This is a label for something that does not exist. You cannot be Orthodox and be in union with Rome, as Rome is not Orthodox, and Orthodoxy is not only limited to the externals of the liturgy, but also to the ecclesiology of the Church (e.g., if you can’t tell from the form of the liturgy, you listen for who they commemorate in their diptychs) . It makes sense for Eastern Catholics to claim this, though, as it reflects the ecclesiology of their communion, wherein what matters most is that they are in communion with Rome, not that Rome is in communion with them. I would love to one day see a Latin Catholic all themselves “Latin in communion with Bkerke” or “Latin in union with Baghdad” or what have you, but I recognize that this is rather ridiculous from an RC view.
From an Orthodox view, I am Coptic Orthodox by virtue of my baptism in that particular church, but I am not any more in communion with Alexandria than I am with Etchmiadzin or Kottayam. I know that this is in some sense similar to the Roman communion (in that a Catholic of any particular church can receive the sacraments in any other particular church), but as nothing in particular rests upon being in communion with a specific Orthodox Patriarch, it doesn’t really make sense to say “Orthodox in Communion with Damascus” or “Orthodox in Communion with Constantinople” or whatever, beyond perhaps specifying what your allegiances lie concerning Chalcedon (“Orthodox in communion with Constantinople” being clearer than Damascus, which has Patriarchs of all the churches).