I've just tried out the new Premier Elements 11. Love the new format and once I found my way around, I really like the flow much better than 10.
I made sure I had my project for 11 set up like 10, and the settings on my Sony HCR-CX260V are exactly the same. When I apply the time stretch (above 100%) and render, the edited result in 11 is severe shakiness. When I used the same footage and applied the exact same % of time stretch in 10, the result was as smooth as can be. I use time stretch in almost every video I create so I really hope there is a fix for this (or you can tell me what I'm doing wrong in 11 that has changed from 10) as the flow in 11 is better. Thanks so much
Have you tried using Time Remapping instead?
Are you seeing the shakiness even after you render the file?
Can you post a sample of this shakiness and link to it so that we can see what you're talking about? "Shakiness" could mean anything from frame rate stutter to a need for stabilization to an exaggeration of hand-held camera movements. We can't say for sure without looking at it.