I think its normal.
Mine does a similar thing when you turn the car Off, the Turbo Timer starts, the HICAS light pops up for a split second then goes off.
Iam not exactly sure what triggers the HICAS light to come on, but put it this way, the car was never designed to have a turbo timer and when one is installed, it tricks the car in still thinking its on, which it is.
So I asume there is some electronic interferance but non harmful...