No it’s not you mate. I went about 5 weeks ago to Patong immigration and they advised me the same thing. Phuket town immigration was very quiet so it was a speedy in and out process 👍
Read the post again. He thought the date was 20th April which would just be 40 days so he was asking if the quarantine had already been reduced to 10 days but in fact it’s a thai style 4 and the date on the stamp is 24th April 👍