Select all always appears if you have no text selected and never appears if you have some text selected. Insane UI decision by apple but that's how it is.

It's still there, it's just difficult to know when it will appear. Sometimes it takes one more tap than expected, or sometimes one must deselect a word and tap again, or change focus away and back again. Very sloppy UI.

YES. WHY?! GOD WHY!?!!?!?!?! I'M GOING INSANE!!