I've been curious about this behavior for years, but I've chosen to just live with it. Enough of that.
Does anyone know why the clipboard is sometimes cleared after certain commands are executed? For example, if my clipboard contains a computer name, and I paste that name into a line that's doing a Test-Connection call and execute it, it may clear that computer name from my clipboard. But not consistently. It happens enough for me to believe it's intentional, but I don't know what causes it.
This is not a PoSH issue, it is a Windows clipboard limitation/oddity. it's an 1:1 thing. The moment anything (you, some other process, action, activity) interacts with the clipboard for any reason, that is what you have on the clipboard.
There are Windows add-ons / extension the purport one to have multiple clips on the clipboard. For example this one I experimented with the past.