I'm not sure that I get your point.
The aircraft is in a max power / max rate climb and is showing a CHT just below the red line. It's quite common on aircraft with less than perfect cooling (which is often the case with something like this primarily designed for performance) for the best climb speed to be set as slow as they can commensurate with not overheating the engine.
Now if it was showing that in the cruise, I'd be a bit worried, but not at a best rate climb.
G