UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.90 Safari/537.36

Steps to reproduce the problem:
http://mmncu.speak-up.com/launch/demo.php 
Go to the page "Warm-up" (click on the upper-right red rectangle).
The site is white-listed in Flash settings. When I click on the speaker icon, Chrome shows that plugins are blocked. I click "Enable all plugins once". After that the sound is played. But I am not able to replay that sound. Also I am not able to play other sounds. The setting at chrome://flags does resolve the problem.

What is the expected behavior?
When Flash content has been enabled in chrome://settings/content/flash  Flash content should be enabled.

What went wrong?
It is not possible to enable flash content for second flash video even when Flash is enabled in Settings-Content. Flash  video cannot be played

Did this work before? Yes Was working fine for all versions <60

Chrome version: 60.0.3112.90  Channel: stable
OS Version: 10.0
Flash Version: Shockwave Flash 26.0 r0