Jan's answer is correct and very good. There are cultures in the world where it is simply expected that God will be acknowledged frequently. It doesn't even necessarily denote particular piety.
To put the matter positively, if you were to exclude such applicants as a matter of course (which you have not done), it would limit the range of applicants you were considering, which would not help you to find the best engineers.
To put the matter negatively, if you were to exclude such applicants as a matter of course, then you would be excluding a fairly specific segment of the globe. I don't believe that that is morally the same as religious or nationality-based discrimination, since you have independent reasons for your concern. But it ought to give any of us pause when our actions (taken for entirely correct reasons) amount to the same action in practice as, e.g., what some right-wing xenophobe would endorse (fill-in-the-blank for your own country).
I reviewed a C.V. for a friend once where the first accomplishment listed was, “Participation in the glorious jihad.” I advised my friend that that probably wasn't the best opening for the job he was applying for. But that's a cultural difference, which doesn't necessarily speak to the candidate's qualification for the particular job.