OK, you need to realise the bias current is way too high and the amp is not 'fixed'- it may be working but it is not right - yet.
Also, bias current 'measurement' is only testing standing current for ONE pair of the output transistors- there are three pairs, each driven by their own 10 ohm resistor, with associated .47ohm emitter resistor. You need to check them all which is a complete pain in those amps.
the rated standing current is 25mA. That corresponds to an output stage dissipation of 9.9 watts in total for the 6 outputs.
580mV corresponds to a dissipation of 244 watts at idle for the 6 outputs! They will cook and burn out in no time.
Clearly, you have a problem. You would be unwise to continue until the root cause has been located.