ARAM Only one team getting Tank options

Ever since “Brawl” was changed to “ARAM,” I’ve been noticing that in some of my games, only one team gets Tank options.

I tend to mentally make note of what, if any, Tank or Healer options are available to my team. Getting only Bruiser options instead of any Tanks is not exactly uncommon in ARAM, so I didn’t normally think much of it.
That was until I started noticing that even when my team didn’t get any Tank options, the enemy team would still show up with a Tank. They clearly got the chance to pick a Tank even though my team didn’t.

I’ve seen this happen several times to my team, and I see no reason to think that this would be exclusive to my team and my games.
I’ve also been in games where my team had Tank options but the enemy team showed up with only Bruisers, so I suspect the same thing may have happened to them.

This has only been happening since “Brawl” was changed to “ARAM,” so something must have changed during the transition.

I hope this is a bug. I can’t see any sensible reason for this to be an intended change.

Edit: Here’s one of the games I played today.
Our team has no Tank options, only Bruisers.
Enemy team still shows up with a Tank, Muradin, anyways.

So their team got a Tank option but ours didn’t.