Might be due to the fact that for lots of ESL speakers, the "ine" in "engine" makes little sense when you consider "quine", "spine", "spline", "brine", etc. The cognitive load to recognize that nginx is really engine-x is that much bigger.

As I like to say, "Give someone a ghoti, he can speak English for a day, tell them how to ghoti, and they can speak English for a lifetime".