Is my resistor damaged?

[nmoore]

Can someone please assist in telling me if my 20Mohm resistor is damaged? My circuit isn't working as it should but I noticed the resistor I-V curve looks weird on the component tester of my oscilloscope (see attachment)

[Haenk]

You did not curve trace it in circuit, did you?

[nmoore]

You did not curve trace it in circuit, did you?

No I did not.

[RoGeorge]

Does the "flat-line then slope" changes into a "slope then flat-line" when the resistor is reversed in the curve tracer?
- If not, I would suspect a malfunction in the curve tracer.
- If yes, then the resistor indeed behaves differently with the voltage polarity, almost like a diode.

I've read some oxide to metal contacts can act as a diode junction, so a high value resistor acting as a diode might be plausible. 

[nmoore]

When I reverse the resistor the flat line does change. Thank you for your reply