The final part of the question is missing. The missing fragment is as follows:
Which of the following professionalism principles is the technician failing to follow?
Answer: Avoid dismissing customer problems.
The technician is probably an expert in the field, he might know that the issue is not a big deal and easily solvable, however, a good technician would never dismiss his customer issues and there are several reasons.
The customer could feel ashamed or might get offended. Also, the customer is paying for a service and he expects to receive a high-quality one.
Even if the issue was not a big deal, after all, it was greatly delaying the customer's work, therefore, it was important and you should treat it as such.