Hello Eugen
It is correct that at low zoom levels, the course (circle and lines) are emphasized by widening the lines.
I introduced this change due to a wish from many users who found it difficult to see the course at low zoom levels. There is a note about this under "Release notes" on the web site.
Obviously, this is a matter of taste, and I'll try to make it configurable in a future version.
Best regards,
Finn