I created a new world in the latest version in survival, with bonus map and chest, no specific seed, and with the "caves and cliffs" experiment enabled. Then I looked at a random grass block and I can see the hitbox displaying not properly as seen on the scrrenshot attached to this bug report.

Bug works with any block that is 1 block width and/or height.

How to reproduce it

1.  Look at any block. Bug is more visible when you are close to the block you are looking at.