Thanks for pointing out these errors.
We refer to errors like this as "Mapping errors", not graphical bugs. Graphical bugs are errors in the underlying graphic engine itself, while the errors you are pointing out here are mistakes the map maker did.
An even better way to point out errors is our bugtracker
http://mantis.themanaworld.org. When you post on the forum, a thread can easily be forgotten, but a bugtracker ticket will persist until it is solved or closed. An even better way to handle such errors would be when you would use the map editor to correct the errors yourself and upload the corrected map to the bugtracker ticket you've created. After you've learned how to use Git and Tiled, this would be even less work than creating and cropping a screenshot.