Is anyone else receiving letters from HMRC relating to underpaid Class 1 NIC? I have received 2 within last 48 hours for different clients, one a charity claiming CJRS and one a business not claiming CJRS. Both refer to underpayment of Class 1 NIC, although both clients are registered for the Small Business Relief for the Employment Allowance. Both statements go back to the beginning of the Tax Year, and I've checked the software and it's showing that the Employment Allowance is being claimed. At first, I thought the charity one was because I was claiming CJRS, and I'd misunderstood and had to claim the Class 1 NIC through CJRS. We've never claimed NIC through CJRS on the basis that employer was already receiving Employment Allowance, therefore definitely no double claim.
Is this just another issue with HMRC software?