It seems you are right. The file seems to be fine on the server side however the other program used for monitoring is not seeing the updated file.

Taking this new information into account, I am assuming it would be a good approach to always force flush after writing sensitive data to make sure they are saved in case of a sudden interruption? That's assuming the buffer never fully write to the file if it is terminated earlier.

Thank you very much for the help! I guess I now have to tweak a few things now to make sure this kind of data lost never occur ever again.