Ok until recently this had never been a problem for me, but when it happened it was super annoying. My edit menu command Paste Attributes command just stopped working in Premiere Pro 2019, neither the menu item or the keyboard shortcut option-command-V was working, and even after resetting the preferences the problem persisted. I did some research and it is was not just me and there is a workaround that always seems to work.
If the menu commands and keyboard shortcut for this stop working, then you can use the right click (or control-click) on the mouse to copy.
And do the same right click on the destination clip and paste attributes this way and it works.
Now I have no idea if this is fixed in newer versions, as it just recently happened to me in 2019, and here is a post about it at the Adobe Forums on how to fix it.
It is just good to know if you run into this, just do it from the timeline, and it will still work.