num
How many requests were still waiting for their space when a replication ended.
A count rather than only a warning, because the warning goes to the log and a parameter sweep does not read logs. Space asked for and never granted means the hold never happened: the closure a modeller wrote is absent from the run, and the replication otherwise looks exactly like one in which nothing was ever meant to close. Anything above zero here says some part of the model did not take place, and timeToCloseZones will be short an observation for each.
It is not by itself a fault. A replication that ends while a closure is legitimately still draining counts here too, which is the same reading a conveyor gives for a load still in transit at the horizon. What matters is the size of it relative to numZoneEngagements.