That mostly suggests a flow issue, but that may be by design as well. Sometimes, though, if the ram can't move fast enough, or the edge isn't sharp enough, it will ball up the fibers of the wood and stall out before it finishes the split. That's when it's DANGEROUS. That log can squirt out of there with amazing velocity and a whole lotta inertia. It's going to break most anything it hits, including you if you're in it's path. Use caution with that thing and always try to keep something between you and it when splitting. I'd be interested to see your build.