Yes, this is normal. When Password Security is turned on or off (and when the setup dialog is opened) it resets the ATA bus. As of Mac OS 9.0, the CD/DVD driver supports bus resets and so responds with a short delay. This won't happen if there is a disc in the CD-ROM drive and it doesn't happen on PowerBook G3 Series (Bronze) models. This does not affect the functionality of Password Security at all.