What's causing this smudgy bloom around faint textures?

Hi, working on a dark space scene, but faint stars and urban lights are causing a strange bloom effect. Even if I turn bloom completely off, this remains. Blooms settings don’t affect it, I tried various anti aliasing settings, didn’t help either. Scalability settings don’t help either. This wasn’t an issue in previous UE versions.

Anyone with some ideas? Much appreciated.