>>50262066So because your eyes aren't good at analyzing things, I'll tell you there are some obvious "tells" on that sheet.
The Japanese text doesn't look handwritten but rather looks digitized. Notes for leaks tend to look handwritten in shorthand.
Another problem is that the fake Grooky pic looks too clean in its lines, no airbrushing and some stiff looking uniform lines. Professional illustrators would have varied or subtle line weights. Some amateur to intermediate artists would have a tenuous understanding on the importance of lineweight and things tend to look jarring for looking too uniform.