Short Term Memory Failure

You can understand

Bulldogs bulldogs fight fight

right? But probably you'd be confounded by

Bulldogs bulldogs bulldogs fight fight fight

due to a failure in the short-term memory in your language-processing system. Now that sentence is sensical: compare

1. Bulldogs bulldogs bulldogs fight fight fight
2. Bulldogs roosters bulldogs fight fight, fight

as two variations on the same grammatical form. One can train oneself to recognize the sense of (1), but it won't happen right off the bat. Your brain is just not set up for it--yet one could still construct a version of the sentence with little arrows in it to point out the relations between the parts, which would make it almost immediately intelligible. Or are the grammars of (1) and (2) different somehow?