The table in our Sovereign
is pretty much the same as your table, and I've hammered away at my computer keyboard on it, as well as having a train layout on it, without it wobbling.
When you flip the table all the way out, you slide the piece with the leg all the way out, don't you?
There are also 3-4 plastic slides where the table attaches to the trailer, if these are worn out or broken, it can cause it to wobble. There's also a piece of plywood the track attaches to, if the screws holding that on come loose, it can likewise cause a wobble.