It's a production company decision to be sure.
The Julie Mao character is such a central core element to the lore. I imagine that during negotiations, cast credit was one o the bargaining chips. If Florence Faivre wants to promote her acting brand, she wants to get credited on more hours of television or motion picture content. If Alcon, Syfy and Space want to use her in marketing, they'll want to use every bargaining chip they can get to ensure she's committed. Florence has an advantage in negotiations because they're going to need her a long time and they can amortize the cost of her contract too if they do it over many episodes. Depending on her career aspirations, it may be a benefit or a hindrance to her how they use her image. They did practically have her nude or appear to be nude in many scenes on Eros. She also kissed a guy at least thirty years older.
This isn't the first and it won't be the last show that has cast members appear as "credit only" on an episode. That's just it, no one really bats an eye at this practice
SPOILER:
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They might also want to keep her around and cast her again as her sister. They're going to use Thomas Jane again too but he didn't get as sweet a deal. He doesn't need it anyhow.