Ah, I’m so sorry. I did not notice you were also the #417/#418 case from back in May (Whisperfish - The unofficial SailfishOS Signal client - #565 by Schniki12).
Now that captcha’s render again, it should be possible to implement their showing when this happens. It’s still weird that you get it and we have not seen it… I’ve pushed it a bit higher on the priority list, but no promises.