Some of the newer or rebranded PI products use the AVEVA "A" as the icon. AVEVA has many other applications than PI. We use some of them.
It's confusing to see PI specific utilities using the generic. The icon is supposed to be a quicker way to identify what you are looking for. If they are all the same, what is the reason to have an icon?
If you don't design a specific icon for a PI-only application, then use the blue & white PI icon as the default. Otherwise, create a new default icon for PI-only applications.
The "PI icon" is the OSIsoft logomark. AVEVA bought OSIsoft. AVEVA has also bought other companies in the past and inherited their programs. Since I download and keep the install kit, user guide, release notes, and catalog files, I store the files for each program in their own folder, and the PI ones will almost always start with "PI", which groups them together.