The controller on the MP Edge definitely incorporates a temperature safety cutoff function to help protect the controller's electronics from excessive heat.
I have never used ferrofluid, so I don't know how much difference it would make to the controller itself, but it should definitely improve the heat dissipation from the stator and windings assembly.
If the excessive heat is being transferred from the windings to the controller via the stator assembly, then ferrofluid should help to reduce the cutting out, but if the heat is being produced mainly by the controller's MOSFETs, then it may not make much of a noticeable difference.
If the motor casing is getting too hot to hold your hand on it, then the stator assembly will obviously be even hotter inside the motor casing.
Alan