Sonoma fails to open .dmg

macOS 14.0 Sonoma fails to open some .dmg with an error "The disk image couldn't be opened. The operation couldn't be completed. Permission denied".

The same .dmg opens OK in macOS 13.6 Ventura.

Most .dmg open OK in Sonoma but I noticed that many .dmg with a license agreement pop-up have the same problem. Such as:

GraphicConverter, TinkerTool, DMG Canvas:

https://www.lemkesoft.de/en/products/graphicconverter/download

http://www.bresink.com/osx/0TinkerTool/download.php

https://www.araelium.com/dmgcanvas

Also Spotify installer seems to fail with a similar error "An error occurred while trying to mount the downloaded Spotify disk image".

This error is not widely reported so I suspect it might be caused by my setup or maybe my oldish Mac mini 2018.

-> Question: Do others with a similar setup experience this?

This is a clean macOS 14.0 Sonoma install to an external disk. No 3rd party virus apps, "cleaning", "optimizing", "speed-up" apps, or VPN.

I have unsuccessfully tried to fix this by:

Safe-boot

Disable macOS internal Firewall

Right-click > Open .dmg

In another new user account

Safari download location from ~Desktop to ~Downloads

Safari "Open safe files after downloading" from OFF to ON

Download with Firefox instead Safari

Dirty macOS 13.6 -> 14.0 upgrade on an external disk

It seems the quarantine flag is no properly cleared. A workaround that fixes this is:

xattr -d com.apple.quarantine file.dmg

But I'd rather let macOS more gracefully automatically handle this.