RStudio 1.1.383 messes up RMarkdown chunk highlighting

I've recently upgraded to version 1.1.383 which has some really nice new features! However in my .Rmd scripts the grayish highlighting is now completely messed up (as shown i the attached picture). Sometimes it's there, sometimes only a few lines within the chunk are highlighted sometimes only the first line of the chunk is highlighted etc..

Additionally the green arrows to run a whole chunk sometimes disappear.


OS: Linux Mint 18.2 based on Ubuntu 16.04
rmarkdown: 1.6
knitr: 1.17

Can you please attach an R Markdown document that reproduces the errant chunk highlighting?

You can create a new Rmd file. It occurs in every of my files.
I realized it only occurs when you quit RStudio leaving the script opened. If then a code chunk is closed and you open Rstudio again the errant highlighting occurs. You can solve the issue by closing and opening the script.