I would suggest you to logout from your Apple ID in Settings app on your iPhone, and then log back in.

Thanks for the screenshots, this is very strange indeed. Has it always been like this or did it work normally before ?

However, if I save on my iPhone and confirm that the data is in iCloud What exactly do you mean by this ? Can you take a screenshot ? The data is stored locally on your iPhone and Mac and iCompta put synchronization data on iCloud for you when you enable iCloud synchronization. You can refer to ...

Can you copy/paste the text from Apple bug report popup ?

Can you click on the File > Open menu item or is it disabled ?

Yes you can do it by creating a new currency in the list of currencies. Set its change rate to 1 and decimal numbers to 0.
You can then go in the report editing screen and select the new currency in the currency field.

If your QIF files happened to be located on iCloud Drive for example, you could also open them in Files app and click on the action button to open them in iCompta 6.

Yes, you just have to select the QIF files in the attachments of your email, click on the action button and finally select "Open in iCompta 6".

I'll take a look at it however do you know that you can simply email yourself the qif files ? It should be quicker than using the embedded web server.

I used your system settings on my computer but I can't manage to reproduce it : Do you have latest macOS and iOS versions or older ones ?