Can't seem to have 2 tank aces in one army?

UPDATE: this is no longer reproducible. I'm not sure what's changed overnight but I don't get the validation error anymore. Thanks for all the input!

Platform: Windows PC

Version: 2.03.19

Repository: Warhammer 40K 8th edition - Astra militarum

I might be misinterpreting the rules so apologies in advance if that's the case.

So I have 2 tank commanders in my list. I've made one of them my warlord but without a warlord trait. I've given this one Master Mechanic (tank ace ability). I then spent 1 cp to activate Tank Ace strat. By doing this shouldn't I gain the ability to give the other tank commander 1 tank ace ability as well? When I try to do that, it triggers the validation error saying I have 1 too many tank ace abilities. I'm pretty sure GW specifically mentioned in a Warhammer community article that it's possible to have 2 tank ace abilities using that strat

https://www.warhammer-community.com/2020/02/06/the-greater-good-astra-militarum-faction-focusgw-homepage-post-4/