Macbook Pro (15-inch, mid 2015) Screen flickers on a certain website on safari

Macbook Pro (Retina, 15-inch, Mid 2015)

Processor 2.8 GHz Intel Core i7

Memory 16GB 1600MHz DDR3

Graphics intel Iris Pro 1536 MB (with AMD Radeon R9 M370X VRAM 2048MB)

OS X Yosemite 10.10.5

Screen flickers frequently when I'm browsing this website - http://funshop.co.kr - using safari(version 8.0.8 (10600.8.9),

This isn't reproducible with latest stable build of Chrome.

The symptoms vary. Sometimes whole screen goes black and comes right back on, sometimes just a top part of the screen flickers.

I tried recording the glitches but screen recording crashes when it happens. so I've recorded it with my mobile phone.

see : https://www.youtube.com/watch?v=RtVniIVe1p8

I couldn't find any answer from anywhere, so I returned the one and got a new replace Today but this still happens.

The funny thing is this only happens on this site http://funshop.co.kr . I couldn't find another one so far.

This problem doesn't happen when I uncheck 'Automatic graphics switching' on System preferences - Energy Saver.

I suspect this is the problem during switching from integrated graphics to internal one but I have no idea why it's happening on a certain website.