Mobile image spoiler showing as option, but not working - in development?

Wish I could post a picture, but for a few months now, there's been what *appears* to be an option to spoiler images on mobile (at least on my Android) but it doesn't actually work. I test it every so often by DM'ing my husband a random picture of one of the pets and trying to spoiler it, and it never spoilers. Is this...just taunting me or is it in development? Or is it supposed to work and has just been broken for months for me?