That is what I expected, but this is what a section of the tree.afdesign file from the first post looks like at 400% zoom:
View quality is set to "Bilinear (Best Quality)" on my Mac, using the OpenGL Display setting. Using the Metal Display setting, sometimes I get the same gaps & sometimes I don't. Any idea why?
EDIT: One way to trigger this seems to be to use the Navigation panel buttons to (for example) zoom to 700% with the plus button & then zoom back to 400% using the minus button. Using the buttons to zoom up from a lower zoom level to 400%, no gaps are visible.
EDIT 2: Using the zoom buttons like above only sometimes shows gaps, & they may appear at different multiples of 100% at different times.
Use Blend Options in the Layers Panel (small cog icon top right) and more specifically the Coverage Map - see image below.
Select all the layers and create the profile seen in the screenshot, actually you can take it right up into the top left corner, I did it that way so you could see the profile lines better.