Vector textures in OpenGL camera drawing with grey underlay

Little hard to describe, so I’m including a screenshot, but I just ran into this problem today in both Harmony 17 and 20.0.2—vector textures on brushes and pencil lines appear in openGL with a no-transparency grey underlay, like the default background colour is showing through all layers underneath? I’m using a camera & z-space to truck in on a scene, and weirdly, before it pushes in, the strokes look fine. It looks normal in the drawing window, render preview, and solo’d layers as well, and bitmap textures have no problems. I’ve tried restarting, adjusting layer, preference, and comp settings, and just installed 20 today when I started having this problem. I’m on a Mac Mini running Big Sur. It’s making my usual workflow in the camera view quite distracting (I love the soft pencil transparency for roughs), so any help would be great! Thanks!