usage of repetition in certain context
You could tell them that the problem recurs every time the technicians go away having fixed it.
Lexico defines recur as
Occur again periodically or repeatedly.
With the example
‘when the symptoms recurred, the doctor diagnosed something different’
The definition and normal use of the word recur includes the idea that the phenomenon occurs more than once so you don't need repetition. You could also start by saying you have a recurrent fault then explain that the fault recurs after the technicians leave having fixed it