Rainwater diverter not diverting all water
New to the forum, so apologies if something similar has been discussed before. We have a water butt connected to the downpipe by a rainwater diverter. I've noticed that a lot of water is still flowing down the downpipe and is not all going to the water butt. Is it normal for this to happen even when the butt is not full? Could anyone recommend a diverter or system that diverts all rainwater? Thanks in advance.