Major Description
The test can fail due to random number collision, claiming there are unreferenced elements for obvious reasons (we rewrite some link). Original Accumulo test has one-stage generation so it doesn't count unreferenced elements as failures, only undefined ones. With 200m longs out of half-long range the probability of collision is approx 0.2%.
Moreover, without some way to debug, it's hard to debug what keys should be looked at in such cases