1647405 - Serious: Thunderbird 78/Lightning is mailing updates to external recipients when I am not the organiser.

Status: UNCONFIRMED

(Calendar :: General, defect)

Description

[me]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0 Waterfox/56.3

Steps to reproduce:

Thunderbird (64) auto updated to version 78 Beta1 & Beta2.
Release notes indicated better handling of .ICS events.

Actual results:

I manage a corporate Calendar (caldav) in Thunderbird
1st bug - can only save to Home/Internal Calendar (with new .ICS dialog). Caldav/Gmail silently fail.
2nd bug - when I then update the Home Calendar event to my Corp Caldav it is sending notifications to all recipients of the original event (which I didn't create).
This includes acceptance, edits, cancellations or caused by moves between a gmail calendar to my corp caldav whilst I was testing.
All messages are going out without my knowledge.
I can see that the edit event (bottom left) has a greyed out "Notify Recipients".
I'm also getting Accepted Events back as are the meeting owners. disturbing.
3rd Bug: profile has been updated, so can't rollback. I will now manually rebuild my profile and revert to Thunderbird 77, and disable updates.

It's going to be interesting for the non technical users.

Expected results:

No emails to go out EVER. This is a reference Calendar. I want no interaction with the recipients in any way, certainly can't spam a large mail list when I'm not the event owner.
Can't be sending cancellation to ALL - I am NOT the owner.

I am getting calls, as others are starting to see this.