M40/Valeo Alt. Pulsing electrics ?

[garry_grigg@xxxxxxx (GARRY GRIGG)]

     I have just sold an E34 fitted with an M40 (1.8) and Valeo alternator. 
      The lights have since developed a pulsing as the regulator controls 
     the charging.  When this happened on my other motor I cured it by 
     changing the regulator/brush block.
     
     Is this a detriment to the motor/battery ?
     Is a new one guaranteed to cure (i.e. is it  a fault or a feature !) ?
     Is this a known problem ?
     
     Garry

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