Small seam like line of tiny bubbles patched drywall

Question

Can somebody please tell me why this is happening and how to permanently fix it? Thank you!

Answer 1

I think that is mesh drywall joint tape showing through.

To fix it you would want to scuff up the wall area where you can see it, with fine sandpaper. Then apply joint compound, in several successively wider coats, sanding between each coat and also after the final coat. Then repaint.