So, I suppose this does also include a problem with Java Edition but I've put this here, as the Bedrock Edition is essentially the issue.

Back in 2016, I purchased Minecraft PE on the GooglePlay store. I have been using the account since then on mobile. Of course, MCPE is now apart of Minecraft Bedrock Edition, which is purchasable from multiple stores on various platforms.

Now, in 2013 I purchased Minecraft Java Edition on a second account, and when Windows 10 Edition was released in 2016, I was gifted W10 Edition for owning a Java Account on the Mojang.com webpage. So, I now own Java Edition, Windows 10 Edition, and Minecraft Pocket Edition, on 2 separate accounts. 

When Minecraft Bedrock rolled out, all the accounts became merged under the Microsoft Account Type so all versions are now Microsoft Accounts.

I added my Pocket Edition account to my Minecraft Launcher under a different profile and the Microsoft Store recognised (at least until now) that I owned the Bedrock version of the game on that account. I was even able to launch and play with both accounts on Bedrock on a server.

Recently, a promotion ran where owners of either a Bedrock or Java Account, could receive the other respective version for free. INCLUDING THE ACCOUNT THE GOES WITH THEM.

So, knowing that I already own Java and Windows 10 on one account, I switched the other account which originated from Minecraft Pocket Edition, to realise that I couldn't redeem the promotion, because I apparently don't own Windows 10 Edition, even though on my Minecraft Profile, It says that I own BEDROCK Edition, which Windows 10 Edition falls under.

1 of 3 things needs to be done to fix this issue, as I can guarantee I am not the only person this has happened to.

Here are the suggestions

1. You should NOT be able to login or launch Minecraft on the Minecraft Launcher with a Microsoft account that owns Bedrock on a NON-WINDOWS DEVICE.
2. Purchases from other stores of BEDROCK Edition, ei: From Google Play, should be reflected on the account as a purchase from another store, or just say what version of Bedrock applies to the purchase.
3. Buying a version of Bedrock means that you own all versions of Bedrock and that should reflect on the respective store pages, so if I own the GooglePlay Edition, and I can prove that, then I should also own the Microsoft Store Version.