UserAgent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.101 Safari/537.36

Example URL:

Steps to reproduce the problem:
1. a frameset with two frames.
2. each frame uses the same linked style sheet
3. the stylesheets are cached with etag

What is the expected behavior?
when the second frame loads the style sheet and gets the status code 304, both frames should be rendered with the loaded style sheet.

What went wrong?
when the second frame loads the style sheet from cache, the styles from the first frame where removed. The page is rendered without css.

Does it occur on multiple sites: Yes

Is it a problem with a plugin? No 

Did this work before? Yes Today, in the morning, before the browser was updated to the current chrome version

Does this work in other browsers? Yes 

Chrome version: 53.0.2785.101  Channel: stable
OS Version: 6.1 (Windows 7, Windows Server 2008 R2)
Flash Version: Shockwave Flash 22.0 r0