Whoh, my spotify just updated to latest version as you. Now I’m, seeing the same.
Looks like they “fixed” their URL parser to now require URL encoded input.
For now try this snippet (not with nice icon, I’m afraid), is it working?:
#popclip
name: Spotify
icon: circle filled S
url: spotify:search:***
(The above block is an extension snippet - select it to install the extension with PopClip)
Edit: there seems to be a secondary issue specifically with newline charcters causing spotify to show the b;ank page now. Selecting from the last.fm page can cause that.
I’ll look into it some more…