Wow, that must be a really oozy nozzle! I'm guessing your extruder isn't retracting when moving over the infill. Most people typically don't care about the excess lines inside their part, so they prefer to not waste time doing a retraction for those moves. However, if you would like to eliminate the, S3D has a nice option to do this. Go to "Edit process settings", Advanced tab, and disable the "only retract when crossing open spaces" option. Now it will retract when moving over infill as well.