Oh well, now I can't reproduce it in the book details output. Removed the invisible space and it displayed fine.
the other day it was returning this instead: (two question marks in a "diamond" symbol)
Attachment 212928
so I had to use...
📂 {#path2} 🏚️ Published in {pubdate} by {publisher} 📈 {#pp}
instead of
📂 {#path2} 🏚️ Published in {pubdate} by {publisher} 📈 {#pp}