I've only just discovered this thread over 2 years late.
I'm getting different results to those described earlier in this thread
I have a Windows 10 PC with both Access 365 & 2010 installed. My taskbar is set to always hide labels.
As a test, I opened 3 Access databases at the same time from their desktop shortcuts. The first shortcut has the Access program path followed by the application path. The other two were standard shortcuts to the app path only.
When I opened all 3 apps using A2010, I got what I expected.
The taskbar icon for the first app showed the individualised shortcut icon and the other two were combined using the standard Access icon
However, using Access 365, I got a totally different and unexpected result. The taskbar showed 3 separate icons which were the individual form/application icons as below:
NOTE: I changed the Access program path from A2010 to A365 for the first desktop shortcut between the above tests