Please report the issue here:
And give your TV make and model in that report.
As a workaround you should be able to disable then re-enable the AMD High Definition Audio Device in the windows device manager instead of rebooting your PC. So that would be less painful to do.
I have the same problem with my R9 390 since a year I guess.
Its pathetic that they didn't solve this serious problem in that time. And as it seems it happens with the new generation cards too, great.
Its time to act for AMD or the consumers will and change their cards.