Sketchup to Lumen RT problems

Hi there, just wondered if you could check  a couple of things for me -

Jaggered shadows (on the face of buildings) Have tried various lighting/time/day/date etc but shadows are still not as crisp as they should be.

Reflections disappearing from windows when zooming in or out, making it difficult to get image right as most of the time right where you want the image is when it 'disappears'. You can make them re-appear by zooming in and out. Very strange but definitely an issue

This happens (both issues) no mater what light setting you are on,