This isn't a Linux issue but I passed it on to the larger Steam team. A fix should be coming in the next couple of weeks but we won't get status back here, so closing.
OK, the fix worked, now it jumps to the inventory, but the popup stays open, and says "Error -302 when loading url steam://close"
I passed this on too and the larger team investigated on Windows. It's apparently working on Windows now, so this is something Linux specific.
The Steam team reported that they now have heard of it occurring on Windows also, so they'll take a look at some point.
Now the main window jumps to the inventory, when the view inventory button is clicked, but neither of the buttons close the popup.
Hello @mtmkls, are you still experiencing this issue on an up to date system?
Now with the mandatory mobile authenticator it's rather difficult to test this.
Closing pending confirmation this is still an active issue.
Nothing extracted yet.
In the "Trade completed" dialog there are two buttons: "Close window", and "View item inventory". The latter used to close the dialog and the main window jumped to the inventory display, but for some months it just closes the dialog.