Time limit for section 143(2) in case of defective return

[sujittalukder]

Dear experts,

I have a query on the time limit for section 143(2) in case of defective return.
In a case return in ITR-6 (company assessee) was filed on 27.09.2016 for AY 2016-17.
CPC issued  notices u/s 139(9) two times pointing out some defects before finally processing the ITR u/s 143(1). The assessee finally uploaded correct return after curing the defect on 27.11.17. The return was processed in Jan 2018 and refund was issued by CPC.

Now in August 2018, notice u/s 143(2) for the AY 2016-17 was issued by the AO. The notice is system generated and gives the reference to the 'return filed on 27.11.2017'.

Now under the circumstances, whether the notice issued in August 2018 is valid or not? Because normally, the time limit for issuing the notice u/s 143(2) was expired on 30.09.2017.

Please guide.