Class 4 NIC automatically generated on Tax Return?

Is Class 4 NIC due on a UK property tax return?

I know this question was asked only last year by Benj, and in spite of having read all the replies (and links), I cannot understand why I cannot seem to remove the class 4 contribution calculation from my tax assessment this year. It was not generated on my 2017/18 return. I am not employed. I am not involved in any other business trade or profession. I only receive rental income from my former residence and 1 other from inheritance.

I have been through my return reviewing all my answers, and I can’t figure out what I have completed differently to generate a different result. The profit figure is lower than last year (empty period). I think I am only generating the property section and using the cash basis. I have rental income from 2 properties, but that was the same last year. I have phoned HMRC for their advice but the person I spoke with was not able to help.

One baffling item though is a page within my online “tailored” return which refers to registering for relief for construction industry sub contractors?

Followed by a page with tick boxes for exemption from Class 4:- for under 16, over state pension age, non UK resident, Trustee or diving instructor, none of which apply.

I also see this on another page which I don’t remember having selected previously: “ I wish to make an adjustment to my profits chargeable to Class 4 NICs” (Optional)

I am hoping someone may have a clue as to what I may have done wrong?

Coraljo