When you shift into Drive, do you let it sit for a second or 2 before accelerating? A CVT transmission works like a Skidoo drive in a way. And when the transmission is cold, the parts get into place a little slower.
Letting it "warm up", only warms up the engine, and does nothing for the transmission.
In fact, and I can't say this is been reported with CVT's, but you should NOT let your engine warm up before taking off, for this specific reason.
The engine gets warm, but the Transmission, transfer case, u-joints, differentials are all cold. So, if you think you're good to go because the engine is warm, and drive it like everything is, you're actually doing damage to the rest.
Think it it like this. You wake up in the morning. Have a hot cup of coffee. Brain is awake, and the chest feels warm. Now start running before stretching or starting at a normal pace to warm up the joints. Same concept.
Not to say that's the cause, but it's possible.