Hey,
The likeliest explanation here is that in your code, the variable or constant you use as the `stripe_account` is empty or not defined. This would lead that code to not send it and our API then assumes you simply didn't send the required header.
I'd recommend adding some logs to debug this and make sure that you're passing what you think you are there. If you do, I'd then make sure that it's the id of a separate connected account and not the id of your own platform. It's possible to connect the platform to itself and in that situation the `Stripe-Account` header doesn't work.
Hope this helps!
Remi