Forest

Had the same issue, caused by the heat around Z4 diode. Fixed by replacing the dead cap C74 (100u/16v) and the diode Z4 (12v 1W zener 1N4742), check maybe you need to replace more components, R2 for example. This area of the pcb is generating “mute” signal for the amp, so no wonder the trick of cutting “mute” pin of tda7265 works sometimes

Nice catch :)

I’ve updated the description, thanks!