Unpredictable Dropper flow

When a "circle" of dropper are connected to eachother, and then powered by a clock, the droppers will skip some dropper jumping to othersv ahead. Not just a block ahead, but like 4 or 5 at most.
http://i.imgur.com/M9KlHv7.gif
This gif show a frame for every clock cycle, not skippinging any cycle. The pistons are powered by comparators with one redstone dust cycling over the dropper circle.