I too was hit by this during my first JSS attempt 2 days ago. (Ubuntu x64, 3.2.0 release)
Since this was my first JS rule, I had many ‘saves’ which resulted in errors.
My rule has a cron trigger every 1s with a today= new Date as the first line, which I thought was to blame, and after adding a delete today after I was forced to restart OH memory usage stabilized.
Guess the delete is not needed. 
What is the best way to recover? A full OH restart or is it sufficient to restart the JSS add-on in Karaf?