Parrallel decoder can emit spurious 0 length models
Strange insertions occur when using optional models in the grammar. When looking at the detailed log file these insertions turn out to have zero length.
A bug in the code generating the labels on the network transitions. The label string was not being cleared inside the loop. So all transitions were getting assigned labels irrespective of whether they came from emitting nodes. The bug was fixed by clearing the string and only setting the transition label if the label string has a non-zero length.