I regularly see the text of Twinned Spell cited as:
When you cast a spell that targets only one creature and doesn’t have a range of self, you can spend a number of sorcery points equal to the spell’s level to target a second creature in range with the same spell (1 sorcery point if the spell is a cantrip).
To be eligible, a spell must be incapable of targeting more than one creature at the spell’s current level. For example, Magic Missile and Scorching Ray aren’t eligible, but Ray of Frost is.
But in my copy of the Player's Handbook, the second paragraph isn't there:
I haven't been able to find an erratum about this, but I'm also not super-familiar with the sources of errata. Where does the language in the generally quoted second paragraph come from?