Just checked the untranslated version and it have this bug as well.Nice, thanks for that. From what i saw, the code might have to be looked into it again because when using the second mirror in recollection room, and being in nepgear's normal expressions, when you want to quit, it puts the picture of nepgear in the video instead, making you stuck. Would have to compare non translated and translated version to see what's the problem. And it's likely not the only problem.
Also, thought there wouldn't be a need to apply the dlc codes but we still have to huh ...
Here's the untranslated game if you or other people want to take a look
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.It seems the Dlsite version doesn't need the codes, this might be due to the shared save system that record the ending you did as well. Put
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in the save folder and it'll load the dlc codes automatically.