Is this just someone new reporting on the established findings from 5 years ago

It looks like additional rigor has confirmed those findings from 5 years ago.

The article says that originally they dated grass seeds in the same layer to 23k years but they can be effected by hard mineral deposits or something?

So more recently they dated pollen, and did some other kind of luminescence testing. So now they have 3x dating methods that all align to 23k years.