The section of the rules quoted above is under the heading...
Unusual Circumstances, "No Birds"
"If unusual and unplanned circumstances occur during the course of a marking test, the Judges can ask the handler to handle the dog, or otherwise compensate for the unanticipated occurrence. The absence of competition allows more flexibility for judges."
This is not in regards to scrapping the test which is covered on the same page under the heading...
Test Dogs
"Changing a hunting situation after a series has been started should be avoided if at all possible. One way of avoiding this, and of avoiding unforeseen and unpredictable situations that would weaken a sound
hunting situation, is the practice of running a test dog, in every series before any of the entered dogs are run. Use of a test dog is usual practice by some Judges, when they may entertain doubts about the exact way that the hunting situation may actually go. Use of a test dog is very often a time-saving device.
The test dog shall not be entered in that test, shall not be over qualified and should be able to accomplish the test.
When a series is discontinued after one or more dogs have run, the Judges shall exercise care to locate the new series in an area different from that which the original series was held. By doing so, they can fairly re-evaluate the abilities of the dog or dogs that have already run in the area used for the discontinued hunting situation.
Yes, according to the rules, if a hunting situation is changed after a series has been started, the dog or dogs that have already run should be re-evaluated (re-run).