MathRandom? No - repeater not working on mobile?

EDIT: Actually, this looks like the repeater itself isn’t working. If I remove the random element and hard code a number for selecting the index, it still doesn’t show as selected on mobile.

I’ve got a repeater that works fine to highlight a random item on load. But it seems to do nothing on mobile (Chrome for android).

Does anyone know how to make it work or is there an alternative way of making it work?

See attached example. randomgrid.rp (55.5 KB)