Sigma 4.7 Bug in ADAU1452 co-effecient calc filter block High Shelf

Hi

Theres a bug in 4.6 and 4.7 in when using the  High shelf

Other filter types appear to  work OK

However when changing the gain (even as little as 1 db  the output goes full distortion max level  

Not sure if this has been reported. But its  happening in SS 4.7, 4.6, even 4.4

Thanks