Snoozed emails can't be opened

[Misfi]

Steps to reproduce:

1. Mark the message as unread (or just don't read it)
2. Snooze it for any amount of time
3. Wait until it's unsnoozed

The add-on will only display part of the mail (I think defined by the preview length) and this:

Error fetching email content: body -> print failed -> 400

It's possible to mark it as read, but clicking on the email title opens a Gmail tab that will load forever:

Note: it's been happening for years on Chrome, even with various devices, google accounts and so on.