I really don't see any reason why anyone would ever want to turn PoM into a dumb non-heal from the smart-heal it already is.
Since PoM only has a 20-yard jump range, but you can cast it on someone up to 40 yards away, you will not be healed if you cast it on a target 21 or more yards away and they take damage. Essentially, if you cast PoM on the tank this Glyph reduces the number of heals from 5 to 1. For no useful reason.
Worse, say you are standing right next to a bunch of folks taking damage that are within 20 yards from you but you are taking no damage. PoM will be FORCED to jump to you instead of someone who needs healing. Sit there. Wait for any damage, then if you do take damage unless that person you cast it on magically happens to still be standing within 20 yards of you it just falls-off. But if they are standing near enough to you then maybe it will jump back to them, even if they don't need any healing at all because it was FORCED to jump back to them.
The power of PoM is that it is a smart-heal. It will heal someone, then jump to another target within 20 yards that needs healing. A bunch of melee taking damage, cast one in there and it will bounce between them. This glyph would have it automatically jump back to you, assuming you stood within 20 yards, whether you really need it or not. This glyph just increases the chance your PoM charges will not be used.
I'm having a hard time understanding how this glyph would do anything other than make your PoM worse. It should be called "Glyph of Failed Mending".
Edit: And if you accidentally cast it on yourself, it can't jump to anyone and it will only heal once. Dumb.