fgetchar returning wrong data

I got a problem using fgetchar to get data from a binary file. The content of the file is (only for testing, the real one is bigger)

Code:

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44 21 3c da be 00 0a ff

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Now i'm trying to read every byte using fgetcar. The result is

Code:

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44 21 3c 1be 00 0a ff ffffffff

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0xFFFFFFFF is EOF, the error seems to happen at 0xDA since replacing it with certain other values works - but then again with other values it doesn't work. Has anyone experience strange behavior of fgetchar?