Inconsistent display of nested updates

[Saroumane]

Summary :
When update-manager asks to update a mix of packages provided by different sources (official Ubuntu, PPAs) there is a strange nested display.

What happened :
See screenshot :
Signal package (from its own PPA) appears at the 1st level, inside there are packages provided by another graphics PPA, and Signal package again.
That does not look consistent, does it ?

What is expected :
Signal package should be displayed on its own line, without nested packages from another PPA.

$ lsb_release -rd
Description: Ubuntu 19.10
Release: 19.10

$ apt-cache policy update-manager
update-manager:
  Installed: 1:19.04.8
  Candidate: 1:19.04.8
  Version table:
 *** 1:19.04.8 500

[Saroumane (saroumane)]

Still happening with Ubuntu 20.04 LTS

$ apt-cache policy update-manager
update-manager:
  Installed: 1:20.04.10.1
  Candidate: 1:20.04.10.1

[Saroumane (saroumane)]

Still happening with Ubuntu 21.10

$ $ apt-cache policy update-manager
update-manager:
  Installed: 1:21.10.5
  Candidate: 1:21.10.5