That has never been an issue before, but that's how I had to circumvent it the last time.

I took the video with my phone, download that file for maximum resolution, and it has all of the info you need.

I can try, it's pretty bad lag. I turned off plumes to see if that would affect it. Nothing changed. It's only with the thruster blocks. Let me try to take a snap shot when it happens. I will do it with single blocks so you know it's not a sync issue.

I'd be willing to make you a gif if you'd like.

It's both with single blocks and large chunks with symmetry. Almost the same lag time, also. THe image of the placed block remaing but it's not registered. Would you like me to make some gifs and plug them in here?

This is my first report, so I don't know what additional information is relevant.