On braking when regeneration is occuring we sometimes get a clunking noise. on 2011 Lexus RX450h

The noise is not predictable but occurs more on light braking. It sounds like a solenoid chattering from underneath the car. Could it be the ABS modulator? Last year the dealer bled the brakes and the noise disapeared for 6 months, but now the cold weather is here it has re-appeared. Some days it occurs a number of times and other days it doesn't occur at all. It seems to occur more during cold weather.

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1 answer 1 comment
should be underr factory warranty
It is under warranty but the fault has now occurred again 6months after they apparently fixed it by bleeding the brakes. I am worried that it will occur some time again in the future out of warranty.