How are you managing the tool change? Could the tool have slipped? (we recommend using the button only to hand-tighten things so that they will stay in place until one fully tightens using a good quality pair of wrenches (13mm low profile and 22mm stubby for the Standard Carbide Compact Router)
I would suggest using a different #102 tool setting, one suited to the material rather than the default.
You would think so but I’ve had this happen to me so I’ve learned to look at tool paths along with the preview. The results in your project get even better if you were to down size your pocketing bit size.
I am running a project now and am getting the same type islands. I’ll probably just sand them or deemed them out but again they aren’t there in the design file.
When the simulation is showing the depths are shown in different color gradients. If the levels are too close to each other the gradients are too subtle for either our eye to see or the graphics card to reproduce in a way we can see it. As Ed said look at both tool paths and simulations.