After self assessment bill paid in full, a new tax bill arrives within 2 weeks!

After submitting my 23-24 self assessment tax return, I immediately paid in full the whole bill, which was due at the end of Jan 2025. This was 2 weeks ago. I still have the document to testify what I was requested to pay. Now, when I logged in my HMRC account, I can already see a new bill popping up, to be paid by Jun 2025. Is this money that HMRC wants to secure in advance for the next year? Or is HMRC making a mistake and not realising that I already paid it in full? How can I check? And if the first option, how is it fair by HMRC to ask money to be paid before I even had the chance to earn it? Thanks

Hi,
This amount is almost certainly your second payment on account for the 2024 to 2025 tax year,  your second advanced payment on the tax you are likely to owe for 2024 to 2025. As the 2024 to 2025 tax year runs from April 2024 to April 2025, requesting this amount in July 2025 means we are requesting the payment 3 months after the tax year which it is for, at a point when you will most likely have an idea of how much you owe. You can find more information on payments on account here:
Payments on account
Thank you.