I think there's been a change in how clipboard works in Windows 10 not so long ago. I was never noticing issues of this kind in prior versions of Windows, nor when Windows 10 came out. I'm only noticing it since maybe a year ago.
The change is that previously, you could copy a piece of text from no matter what application, close that application and paste it somewhere. But now you will find the clipboard empty. The text you copied only lives for as long as the application that provided it is alive. It's super annoying and makes trivial actions a pain. Is there a way to disable this new "feature" and make clipboard persistent?
I'm running Windows 1803 and 1809 on PCs where I notice this behavior.