Adopted child listed with adoptive parents on birth index as birth parents?

So a relative I'm researching struck me as odd in their birth order and age for various reasons. I remember wondering if it was possible his sister was actually his mother. But I had no evidence to support that so moved on. But not that long ago I actually came across an online history of the family on Ancestry and in the notes they specified this person WAS in fact adopted!

The problem is there is a Texas Department of Health Bureau of Vital Statistics record that lists births with the child's name, birth date and parents. The record clearly lists the two adults who would have adopted him as his parents. I had always assumed this meant they were the birth parents. This was in 1947. Is it possible the adopted parents could be listed on those records?

The adopted child is technically my grand uncle. I am a dna match with the son of the adopted child/ grand uncle. And the son should be my 1st cousin 1x removed. Ancestry shows him as being my 2nd cousin or half 1st cousin 1x removed. We share 273 cm. Is that my answer? Does that indicate his father might have in fact been adopted by his grandparents?

I hope people can follow all the details of this.