Unit firing at power up due to the way 150R (R7) is connected to positive rail and transistor collector (Q2) must pull down to turn off.

Same as with Gompy's old 16f628A ignition that had switching for either a CDI or TCI system. In John's CDI power board he shows an alternative connection for R7 depending on whether you use points, hall effect directly or input from a certain pic micro circuit.

If the circuit was changed so that 150R (R7) was connected to ground and the transistor collector (Q2)connected to the positve rail, then this would not happen. It probably requires software change on GP1 though.