[Bug]: Not mounting inserted CD in running *nix guests

[irwir]

Version

7.2.2

Host OS Type

Windows

Host OS name + version

Windows 11 25H2

Host Architecture

x86

Guest OS Type

other

Guest Architecture

x86

Guest OS name + version

Ubuntu, macOS

Component

Storage and Virtual Disks

What happened?

There are 3 ways to add CD image to VM: in Settings/Storage, by using VM's status bar icon and Devices/Insert Guest Additions CD Image... menu item of host window.
Attachments made in Settings before boot mostly work well.
So far, no issues were noticed with Windows guests of different versions and bitness.
Probably this began before 7.1.10, but this was not verified (certainly, 7.1.12 and later misbehave).

Any CD image should do, and GA .iso would be used below.

I. Ubuntu guests: Server 25.04 (25.10 beta) with GUI
Inserting disk image via status bar used to mount the drive (and maybe suggested autorun).
The normal behaviour of disk icon and its context menu in Gnome's side panel was:

• left click opened Files window.
• right click showed context menu having New Window, Unmount and Eject.

Now left click does nothing, context menu has only New Window and Eject - no Mount or Unmount items.
Left click on New window does nothing.
Menu item Devices/Upgrade Guest Additions... fails with exit code 2, however it is possible to execute cd /media/<user>/VBox_GAs_7.2.2; all files are readable and manual install is possible.

Icon and menu get "fixed " on wake up after automatic screen blanking.
But if disk was ejected, next insert would have the icon "broken" again (same for images attached before boot).

Somehow, for VirtualBox.iso directory /media/<user>/VBox_GAs_7.2.2 is created.
Command mount lists the correct entry:
/dev/sr0 on /media//VBox_GAs_7.2.2 type iso9660 (ro,nosuid,nodev,relatime,nojoliet,check=s,map=n,blocksize=2048,uid=1000,gid=1000,dmode=500,fmode=400,iocharset=utf8,uhelper=udisks2)

II. macOS guests: Catalina, Big Sur, Monterey
Attempt to insert from status bar ends with this alert:
The disk you inserted was not readable by this computer.
Ignore Eject

Eject and reinsert never help.

No directories created in Volumes, no additional entries in mount output.

Attaching CD image in Settings before boot is fine and there are no more issues with the drive, because disk images (.iso, .dmg) could be ejected, inserted - and would be properly mounted.

How can we reproduce this?

Ordinary installation of VB and guests, then insert CD image.

Did you upload all of your necessary log files, screenshots, etc.?

• Yes, I've uploaded all pertinent files to this issue.