too many display and sketch style tags too judge where the conflict is (in a reasonable amount of time anyway). Judging by your top image I would remove all material and sketch tags, remove the sketch effect in the render settings then start fresh - add sketch again and set the settings so you get the look you want in the sphere and vines and only add sketch style tags to the crystals. The object being to keep it simple, do as much as possible with the main sketch settings and add style tags only where necessary.
Thanks Brian. Unfortunately this is 1 section of a much longer camera pass and removing the S&T materials/effect in render settings will likely result in more issues.
That said, i did systematically remove and add the tags in this section and couldn't get it to behave as required. Oddly I have the same set up earlier in the camera move (vines/orbs) and that works properly.
Really lost as to what's going on. May have to be a compromise and hope its not that noticeable since they're moving quickly.