I'd love a hint! Based on your response, the only other thing I could imagine is if the tile could stack or something. I did try to put a tile in the "blank" space but it did not work
The Ectovus is checking for unoccupied spaces around it (and dislikes having too many of those). In the specific level this leads to a somewhat unintuitive situation, where the left side does not allow both to satisfy their needs, in spite of looking more promissing.
