It means you have selected the entity to trace at the wrong point. The trace will always go through the point on the entity where you selected it.

(Note that it might go the wrong way around untill you have moved the mouse enough from your starting point to pass the selection point)

Ah, I see. It is just the name of a tool from that style. I don't really know the purpose of it, but it is just drawing a regular polygon. Mayby it is intended for drawing polygons that you can later use a cut operation against, but there isn't anything cutting or cutted in the tool itself.

The resolution during export is the same as on screen, it picks the appropriate resolution based on the actual size of the symbol in the image. You can force it by selecting Very High before exporting, but it shouldn't normally be needed, as you won't get a benefit from using the very high symbol as a base if it is only going to occupy 10px in the final output anyway....

1. Not following you here. Where did you find a cut polygon option?
2. Yes, creating your own tool will work fine. Just remember a tool will belong to the current style, the tool won't automatically be available in other map styles unless you manually load the tools from another style.

Joe is right about the resolution mode here.

What happens here is that CC3+ keeps each image in four different resolutions, so it only shows the resolution needed based on your zoom level for faster operation.

However, those affected trees of yours are not the same size as the rest of the trees, they're about 10% smaller. This means that when you zoom out, they switch over to lower resolution versions a bit earlier than the others, and if you hit just the right spot when zooming out, those trees have switched over to the lower resolution version, while the others have not.

You can fix this as Joe points out by using :CC2RESMODE: and forcing them to always display very high. This may not be a good idea for a big complicated map, but for this small map the performance difference should be minimal.

This shouldn't affect image exports, unless you export it at rather low quality, in which case the same can happen for the same reason, with the solution being the same.