I've had this problem ever since day 1 of L4. It happens with either L4.0 SR3 or 4.0 RC1
If logos already running and I plug in my phone than as soon as Microsoft Active Sync initiates, L4 crashes.
If my phone is plugged in and I start L4, it crashes after displaying the logo.
It is not a major problem, however it is a nuisance.