I have the same TV Box - MXQPRO4k. I used the mxqpro4kpro image from ilmich last update. Everything runs great with 720p resolution. Still shows a red light when on instead of blue, but whatever.
I solved the problem by putting an old version (LibreELEC-RK322x.arm-9.2-devel-20201121105345-2b69065-rk3228a-mxq4kpro) then updating to the most recent (LibreELEC-RK322x.arm-9.2-devel-20220112105523-3ce5dd4-rk3228a-mxq4kpro) and now the led works correctly again.