Wall Stains

[Stone_House]

Hi all. I have some strange pink staining coming through freshly painted walls. It had been papered over at some point, I had removed the paper and exposed some wood behind rather than plaster. It looks like it had been previously painted so rubbed that back to uncover a strange red ‘paint’. It feels oily. I’ll see if some stain blocker works but wondered if anyone knows what it is.