VoiceOver on iPhone translate numbers to letters in my homebanking app

Hi everyone

After the latest update of the app to my homebanking, now VoiceOver on my iPhone translate numbers to letters, e.g. when I read character by character, and if I lets VoiceOver read the informations on the hole screen.

The number 3.228,63 is translated to the text three thousand two hundred and twenty-eight comma six three.
If you look visually on the screen, and also take a Picture via the build in option, the number is written with numbers. My homebanking support has not heard about this problem before for sighted people.

Therefore:
1. Is there a feature in VoiceOver that can translate numbers to letters, if yes, how can I disable the feature?

2. Have other people here also heard about the same problem in other apps?

3. If there not is a feature in VoiceOver that can translate numbers to letters, is there so a code you as developer can write in aps, so VoiceOver translate numbers to letters?

I earlier has written to my homebank regarding better accessibility for users of VoiceOver in there apps, but I am not in the beta-testing team, so therefore I am not sure what they do for better accessibility until the app is released in the full version.

I have tried to change to another voice/language, but with the same result.

My iPhone is an iPhone 6, 64-GB, with iOS11.0.3 installed.

Thanks in advance for the answers, and have a nice day.

Regards,
Anders