Not sure, I am at office now will check in the evening, but this pair is output in my system. Please check if these 2 pairs have any split/bonus in the last 200 days, in which case pValue would be impacted. You can quickly check for splits by plotting the pairs as follows:
returns[['IL&FSTRANS','ITDCEM']].plot()
returns[['IL&FSTRANS','ITDCEM']].plot()