Originally Posted by elbee
Well, it is the edge of the tape, but it is not really lifting per se, because when I push on it, it doesn't move. But, I don't really know if I should rip it out and start over or just put more joint compound on top of it. I just don't know what it should normally look like.
You can pry that tape edge open a little. Then, using a taping knife, push more compound under it. Wipe the tape flat, and re-coat.
Often, if you over-wipe the tape (compressing and pushing the compound out), too much compound may be removed. This results in lack of adhesion, and air bubbles.
That could have been what happened. You may have over-wiped the paper tape. If there is not enough compound (which acts like a glue/adhesive), then the tape will separate from the sheetrock. That appears to be what has happened to that edge.