Hi. Im having this problem.
RX580 connected to LG tv. When using old games at fullscreen, sound dissappear..
Example NFS underground, Streets of rage v5 (homebrew). When I switch back to windowed, sound come back, switch to fullscreen, no sound. TV shows 480p when fullscreen on this games.
Using latest radeon drivers, but happens on older ones too. Windows 10 x64