My JPY debit card always works for GBP, EUR, USD top ups. After 6 hours on the app chat with Maciej, too much back and forth between lunch and meetings etc…
According to support chat Maciej, the following currencies are NOT supported for top-ups via debit bank card yet - AED, CAD, HUF, INR, JPY, MAD, MXN, QAR, THB.
Also, the error message you receive when you do top-up with the above none supported currencies is too vague “We’re sorry, something has gone wrong. Please try later.”
Not sure why, only been told “the issue is being investigated”. However the error message should say it is not supported.