MC2 controller relay protection. Failed MELF resistor DOUT

I have 2 different units both using MC2 DOUT to control a large solenoid. Both have flyback diodes installed correctly near the relay. After several years of use, both have the MELF resistor for that DOUT failed inside the module. How can i prevent this from happening to a new or repaired module? Fire a smaller relay to control the large solenoid? Add a capacitor to the DOUT line? Another diode inline on the DOUT line?