Text pop-up not showing during Play

This hasn't been a problem before I don't think, but whilst trying to set up some text pop-up on my sign post, it displays in the Scene tab, but for some reason it doesn't in the Game tab. Not even if I play it in full-screen/Maximise on Play. It activates/turns on when the character steps into a nearby trigger zone. It's clearly working based on the Scene view, but I don't understand why it doesn't in the Game window. Or how to fix it. The text is TextMeshPro, which is the same text type I used in a previous scene, and the controller button is an Image.

 

Could be a Z issue or if you are using a mixture of normal <TextMeshPro> and <TextMeshProUGUI> objects where these happen to be sharing the same font asset and material preset.

 

Checked my previous scene... The canvas there was set to World Space and had a Sorting Layer set up.