ID 414496 - [S] To Editorial: Email notification only shows panels added/changed since previous Revision as "new"

Problem summary
Email notification for publishing to editorial only considers as "new" panels that were added/changed since the previous Sequence Revision rather than since the previous editorial publish.

Customer reported version
Flix 6.1.2

Customer reported platform
macOS 10.14

Steps to reproduce

1) Create a Sequence with one panel, save this Revision and publish to Editorial.

2) Add one panel to the Sequence and save this Revision.

3) Add another panel to the Sequence, save this Revision, and now publish to Editorial again.

4) The publish email will notify about 1 new panel, rather than 2. The contact sheet shows the correct information (2 new panels).

Expected behaviour
The publish email should consider "new" any panels added/changed since the last publish to editorial.

Actual behaviour
Only panels changed/added since the last Sequence Revision are considered "new"

Reproduced by support

This bug has been reproduced in:
6.1.2 - Windows 10 - macOS 10.14