Analogue TV Capture card "muted" by some websites

I have a Lifeview 2000 Analogue tv capture card and use TVtime to watch tv on my pc. Whenever I visit a site with a flash player and the video starts to play the tv input seems to be muted by either the flash player or a script on the website. HTML5 video sites do not do this so I assumed it is somehow flash related. I uninstalled all flash plugins and try only to use HTML5 where possible. However, there are still websites that "mutes" the tv card, eg. https://login.aliexpress.com/
The only way to get the tv sound playing again is to change channels or to change the input from stereo to mono and back to stereo. It also affects mencoder when capturing the tv input. When the sound is muted alsamixer still shows the master and capture inputs and outputs as unmuted and at 100%.

I run Lubuntu 17.04 (but this sound issue has been with previous versions as well)

Output of arecord
~$ arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: Intel [HDA Intel], device 0: STAC9227 Analog [STAC9227 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: Intel [HDA Intel], device 2: STAC9227 Alt Analog [STAC9227 Alt Analog]
  Subdevices: 2/2
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
card 1: SAA7134 [SAA7134], device 0: SAA7134 PCM [SAA7134 PCM]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

and aplay
~$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: Intel [HDA Intel], device 0: STAC9227 Analog [STAC9227 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

Any ideas?
Thanks