Minecraft license on 2 Apple devices under the same child account is not working

Hello,

I have this scenario:

I have more kids and I bought Minecraft license from Apple store for 2 of them.

Both kids have an iPhone and an iPad M2/3 as well; each have their own Apple children account.

For one kid the Minecraft is working on both devices under the same Apple account and Minecraft license.

For other kids, we were able to install only on the iPhone, for the iPad it ask for payment even if the Apple account is the same as on his iPhone.

I know the fact that the Minecraft is not using the Family sharing anymore and that's why I bought Minecraft for each of my kids but why is not working for one kid.

We restarted the devices, we double checked the Apple id's.

What can we do more to be able to install Minecraft on the iPad under the same license?

Thank you,