That might happen if your zoom setting is too wide, we optimize LOD levels taking 0.70 as a reference, which is universally considered to be the most realistic.
This doesn't mean that you can't use wider settings, just that we usually test and try to be sure everything is working correctly for 0.70. You will usually be able to go as far as 0.50, but we don't test or design to ensure that zoom level at all places.