The PA platform's icon—which I have set in Windows to always be shown—will occasionally be relegated to the hidden icons popup window for notification area icons.
Background info and defining terms
In Windows 10, the notification area is the section of the taskbar towards the right end (for left-to-right languages), just next to the clock. It shows icons of programs that are currently running—assuming they dictate that they should indeed show an icon in that area, of course. Typically, only programs that would be considered to be "background programs" select to display an icon in the notification area (as opposed to the regular running-app icons in the taskbar). The PA platform is one such program.
Windows 10 has a feature that allows the user to selectively show or hide specific notification area icons. Hidden icons are put into a little pop-up window triggered by an up-pointing chevron icon ( ^ ) next to the shown notification area icons. The preference on which icons to show or hide is remembered across restarts, etc—it's (supposedly) permanent, not temporary.
Possibly relevant info
According to this SuperUser thread about a similar problem, just with the Slack icon, this issue can be caused when program updates change the .exe. Specifically, the
AppID was not being set in the installer, which prevented Windows from recognizing that a new install was connected to a previously-existing program (see comment here).
Is this possibly the reason why the PA platform's icon sometimes gets relegated to the "hidden icons" popup window? I have to say that I suspect the issue might be caused by something else, as the platform's' self-updating doesn't happen nearly as frequently as the icon disappearing into the hidden icons popup does. ¯\_(ツ)_/¯