I'm not famliar with the system on this model, but looking at the diagram for the thermostat in the hondaparts link, I take it that the system is a "thermostat on inlet" design.
"Traditional" systems have used a "stat on outlet", i.e. it is at the exit from the engine (cylinder head) and opens to let coolant go TO the rad. These would normally start to open around 88C.
A stat on inlet is sited between the rad bottom hose and the coolant pump inlet, but also uses the by-pass flow mixed with bottom hose flow into the pump inlet as the operating temp control. These are usually around 80-82C, based on a typical 8degC delta-T across a rad. As the engine heats up, the outlet and thus by-pass temp reaches 80C and the stat starts to open to allow coolant IN from the rad bottom hose. This immediately acts on the stat so if it begins to over-cool it will react and close a bit. These systems generally give a much more stable temperature, a stat on outlet has to wait for the cold water to go through the engine and reach the outlet before it can react, leading to significant temperature swings and thermal cycling.
It ought not to be possible but could it have the wrong spec stat fitted, or could it even be fitted the wrong way round?
A others say, open road use doesn't need a fan, that could be a red herring.
The basics to check would be that the coolant system is actually full, that the coolant is circulating (feel hoses as it warms up), and that the rad is clear air-side. Does the rad bottom hose to engine stay cold while the engine warms up and then starts to get warm as the stat begins to open? Stats should normally fail open, so whether inlet or outlet design it should default to full cooling. Very unusual to fail closed (but not impossible).
It's not unknown for impellers to lose vanes but it is new that's extremely unlikely, but feeling hoses as it warms up at ide will let you know if it is circulating.
As suggested, an IR thermometer or a thermocouple on a multimeter would enable you to confirm the apparent temp is actually accurate.