When you have outline selection off and look at a lectern that has a book a weird stripe thing appeaers.

How to reproduce:

1. Turn outline selection in the video settings to off.
2. Place a lectern with a book inside and look at it. 

Update: This was an issue in 1.13.1, but did no longer work in 1.14, so it seems like it got unconsciously fixed in 1.14. (It wasn’t mentioned in the changelog)