After I was able to upgrade to a D'deridex-class warbird, I found the ship appeared in-game as a dull blue shade with azul-ish highlights instead of the classic romulan green-on-green scheme.
It's not one of the alternate material options, I went into the shipyard to try to change it and swapping through the various options does nothing. The color options also show a blank. Not black or white, but no color at all.
I've since levelled up and upgraded to a Ha'nom-class, but now the issue affects it, and the old ship is just fine. Switching vessels and flying around and even logging out and back in don't help.
This isn't the biggest problem in the world, everything else is just fine. It's just been getting progressively more annoying. I'd rather have ship look how it's intended to look. And for the life of me, I cannot find anyone else with this problem, or least no one who's complained about it.
What kind of space items you have equipped on your ship?
Some item sets do change ships appearance. Try to right-click on your equipped shields and "disable visuals".
It looks like you have item set visuals on.