so I tried using 1Password X on kraken.com (cryptocoin exchange) which I set up to use 8-digits long 2FA per option. I actually have set up four of these 2FA. (one for login, for trading, for funding and so on)
This works extremely well in the Windows app, iOS app and on the website, yet 1Password X only displays one single 2FA with only 6-digits. I can't tell you which one however. I set up titles, but the one displayed has "two-factor" as title. The remaining options I've set up display a weird super long link that starts with otpauth:// instead of actually displaying the digits.
I did report this back then to the iOS team. They fixed it. So maybe ask them how they did it.
1Password Version: Not Provided
Extension Version: Not Provided
OS Version: Not Provided
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