stefanoV de plhrhV caritoV kai dunamewV epoiei terata kai shmeia megala en tw law.
The focus of the verb should be the word epoiei which is a verb that is imperfect tense. This is still a past tense verb so the verse is still talking of an action that is no longer happening, but it is a progressive. It can be translated as, “was doing”. The entire verse can be translated literally as,
“Stephen, but full of grace and strength, was doing miracles and great signs among the people.”
This is speaking of something that was being done sometime in the past but is not being done now.
Sorry about the mistake.