UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.84 Safari/537.36

Steps to reproduce the problem:
Try running this in console:

for (let i=0; i<4917; i++) {console.log(typeof null === 'undefined')}
All false.

for (let i=0; i<4918; i++) {console.log(typeof null === 'undefined')}
All false except for one.

for (let i=0; i<10000; i++) {console.log(typeof null === 'undefined')}
4917 false
5083 true

for (let i=0; i<20000; i++) {console.log(typeof null === 'undefined')}
4917 false
15083 true

What is the expected behavior?
Always false.

What went wrong?
Not sure of the cause, but the problem is in the steps to reproduce.

Did this work before? N/A 

Chrome version: 51.0.2704.84  Channel: stable
OS Version: OS X 10.10.2
Flash Version: Shockwave Flash 22.0 r0