Is "during the middle of" proper English?

In this question on the Movies & TV Stack Exchange the question starts with the following observation:

Actor Philip Seymour Hoffman, who portrayed a character in The Hunger Games, passed away during the middle of filming for the Mockingjay movies.

I am not a native speaker, but to me this sounds incorrect. It looks like a combination of "during filming" and "in the middle of filming" (and even "during filming" doesn't feel right).

Solution 1:

In terms of getting the message across, I don't see any problem using during the middle of in the sentence. However, it would be more idiomatic to use during the course of or during the process of as the below Ngram Viewer shows:

When you put during the middle of filming, there is no result in Ngram Viewer as follows:

Edit: As suggested by the below comment, in the process of filming and in the course of filming seem to be more broadly used than during.