An Audio Module heating up
The problem maybe  Phase Margin is negative at unity gain (See Spec Fig 2) unless loaded with 560pF. See table...  65 deg unity gain phase margin with 8 Ohms 560 pF.

Check DC output across the load. If any DC, add DC blocking to the interface if your source is DC coupled with offset.  The 1uF draws power for 20~35 ms after Standby disable. This can be cancelled by RC matching input cap to rise at the same RC time constant.   


  THis is a transient heat problem with coming out standby in this design on a 8 Ohm load.  Starting to heat up is OK. Continuing to heat up is NOT OK.  If not continuing, it may be a non-problem. 



If OK but you want to reduce the trasnsient heat effect,  change 1uF to   0.1uF. but note"In the high frequency region, if Cs is lower than 1 µF, it increases THD+N and disturbances on the power supply rail are less filtered."


You have 3 choices;


increase gain to 20dB or x10 with Rf/Rin ratio.
Add 500pF to each output. which at unity gain does not affect closed-loop BW significantly.
some compromise of above.  R5=100k  gain ~x5 14dB , phase margin >30 deg stable  then test Step response for overshoot and add load Cap up to 560 pF


It seems like the OEM designer did not figure out these issues.