Same issues here.
With the big New Holland wheel loader and log attachment, you can only grab one log at a time by pinching it between the ends of the bottom "fork" and the moving clamp part. And sometimes the log slips out, still. Trying to get more than one log is pointless, they will all start falling out from the sides immediately. Or they will start shaking violently on their own, making the entire wheel loader jump around on the ground.
Logs feel like they have zero friction when you're using any implements to handle them.
Once you have a fully loaded trailer and tie the load with the straps, the logs still have some weird physics going on that sometimes cause the trailer to randomly fall over when you're driving in a straight line. And sometimes the trailer falls over to the left, when you're making a slight left turn. How is that possible?
Log physics are very broken at the moment. Please fix it!
Also, the MAN log truck has bad physics. When you rotate the loading arm to the side, extend it a bit and then move it up and down, the entire truck jumps around. With the support legs lowered.
In FS19, logging feels like an afterthought that was rushed into the game at the last minute with no testing of how anything works.
I don't understand how things have gotten worse from FS15, in which logging was a lot better, at least from the physics stand point.