Waste: Yes it could most likely be near the hot end if it's related to temp.
What sort of thermistor have you got? An axial one (cylindrical, one lead goes in one side, and another lead goes in the other) or radial (both leads come out the same side, usually looks like a bead or tear drop).
With the radial ones, if your insulation moves away from the tear drop/bead shape, you end up with exposed wires that could touch each other, as depending on the thermistor, some of them are very thin.
What sort of thermistor have you got? An axial one (cylindrical, one lead goes in one side, and another lead goes in the other) or radial (both leads come out the same side, usually looks like a bead or tear drop).
With the radial ones, if your insulation moves away from the tear drop/bead shape, you end up with exposed wires that could touch each other, as depending on the thermistor, some of them are very thin.