Precision 5530 power issues, Date/Time errors

I support 10 or so Precision 5530's in an enterprise environment. So far, we've had multiple with "sticky" power functions, where users are unable to power on the machine and I've needed to hold down the power button for 20 seconds to flush residual power before booting normally. They boot to a Date/Time Bios error and then boot to Windows OS. Anyone else having similar issues?