A previous article presented a technique to compute the least-cost error re
pair by incrementally generating configurations that result from inserting
and deleting tokens in a syntactically incorrect input. An additional mecha
nism to improve the run-time efficiency of this algorithm by pruning some o
f the configurations was discussed as well. In this communication we show t
hat the pruning mechanism may lead to suboptimal repairs or may block all r
epairs. Certain grammatical errors in a common construct of the Java progra
mming language also lead to the above kind of failure.