Mage cast random Polymorph

I’ve been trying to make a macro to cast a random polymorph, but I can’t make it work and none of those I find online do either.

I’m currently trying this but all it does is cast the first one in the chain 100% of the time:

#showtooltip
/castrandom Polymorph(Black Cat), Polymorph(Sheep)

Are you sure you put the macro on your bars? It’s working as intended for me, in Retail.

Tooltip always shows the first one but it casts both.

I tried it again on some mobs and it appears to work. But there’s definitely some weird interaction on critters (I tried it on them the first time). The macro appears to always cast the same version so long as you keep spamming it on the same critter…

On first observations, the effect on critters appears to be randomized everytime the macro is used on non-critters. So I guess that’s a bug on Blizzard’s part ?