Shudder/Hesitation from park to drive

I really wasn't sure what to search on the forums but I did poke around a bit and didn't find anything... please link me if there's a similar thread:

The past two mornings, I unhook from my charger, turn the car on, foot on brake, go from park to drive. I press the accelerator slightly and I get what I can only describe as dropping the clutch when you are trying to learn stick the first time. The car scoots forward a foot or two, and clearly doesn't want to. I immediately take my foot off the accelerator and hit the brake. Then I gently go back on the accel and everything is fine, like nothing happened at all. Furthermore, it doesn't do it from park to drive any other times during the day, even after sitting at a restaurant for 6 hours.

Has this happened to anyone before? Does that even make sense? I just got a brand new drivetrain under warranty, and I don't want to make a bunch of hoopla at the SC, but this is a weird problem to have.

Wow that was fast... I did wash the car yesterday, although that doesn't account for the previous day (no water to speak of here in SoCal otherwise). I'll keep an eye on it tomorrow morning, and probably next month when I wash again.

Gonna bump my old thread. This continues to happen on a once to every other day frequency. I have brought it up with the service center on my next visit. The description above still stands, I describe it as "dropping the clutch" on a manual car. Another way to describe it would be: Sitting in traffic with foot on the brake. Remove foot from brake and put it on the accelerator (gently or with force it doesnt matter), and there is no response. It takes about 2 seconds to kick in (gear selectors turn red from grey, and the power meter (orange) goes to a dotted line and wildly traverses the half circle display), and I'm jolted forward. I would also note that this freaks me out so much that I rapidly slam on my brake depending on the situation to avoid rolling backwards into people. Scary.

Hope they have an idea as to why it does this.

Bump again, got a DU replacement out of this. I couldn't make it happen on command but i wrote down the times it did happen in the days prior. They had a SC tech look at the logs and apparently I need a new DU...