Resistor Mounted On Top of IC?
It would appear to be a thermistor, for which a 3% temperature coefficient (usually referred to as "alpha" in the datasheet) is not unusual.  1.8k is probably the resistance at 25C.

It's probably a temperature-feedback mechanism, either to protect the transistor array from overheating, or to correct the behaviour of the circuit with respect to the temperature dependence of the transistor array.  As BJTs get hotter, they conduct better.

Vishay intro to NTCs.  Yours may be positive or negative, who knows?