Email with "french" encoding not decrypting via web

A friend encrypts a message in key base web site, and sends it to me via gmail.

I cut and paste the message from gmail into web "decrypt" page and enter password, click button.

The icon sometimes changes color (red/blue/red I think) but the password blanks and the message does not decrypt.

I can decode other messages just fine.

Any thoughts? Things I can try?

The report provides no repository file, test, or entry point. Start by reproducing the failure with the copied Gmail message and compare it with a message that decrypts successfully, recording the encoding and exact pasted text. The issue needs triage and a confirmed scope before a newcomer can implement a change.

Written by the indexing model from the issue text.