Unity In app purchases - non-consumable Duplicate Transaction on Android

Dear friends,

I am trying to implement Unity Purchasing functionality.
Everything looks quite straight forward and works as well. However looking at the logs during the initialization of the purchases I wonder why do I get “OnPurchaseFail” and reason DuplicateTransaction.
This happens after I buy non-consumable product.
I know that on Android the OnInitialize() triggers automatic purchases restore, that’s fine but then why it fails?
I have followed this guide: Unity IAP - Unity Learn
Nothing added from myself.
Is there a way to check what goes wrong? Or is it just a normal behavior and I have to live with it?

If any code is needed - I can share it, but it’s pretty much the same as at the guide-page.

Hope to hear from you soon!
Thanks in advance!

Same issue here. I think I’ll just add an ignore if.