UI Toggle Component Broken?

I'm spawning button-style toggle prefabs into a scrollable viewport via a script I made. It mostly functions as intended, but the button images don't display consistently. I triple-checked all the settings, and there should be no scenario for the buttons to disappear. However the buttons behave as such:

-They spawn invisible, with only the text on the buttons being visible.

-When I mouse over the buttons, they transition into their highlighted color. When I move the mouse away, they change into their normal color, and are visible.

-When I click on one of the buttons, one of the others at random will disappear again. (with the text still being visible)

The behavior is actually a little more complicated and nuanced than that, but I haven't quit nailed down the pattern. I think I might just use buttons and handle the toggling behavior manually, but I'd like to do this "properly" and hope somebody might have a solution, or at least some thoughts on this?