precursor and fragment relationship in .mzml file

I am a new intern at a dry lab looking at mass-spec data from our wetlab partner.  The wet lab is doing DDA using an Agilent 6550 Q-TOF to analyze some biosamples.  When looking at the output .mzml file, I am noticing something unexpected in the m/z values of the precursors and their associated fragments.  For example, in observation #1, the precursor m/z is 535.772527 with a charge of two.  The fragments array associated with this precursor has 331 fragments.  The sum of the m/z of those fragments is 165,958.62561798096.  My understanding is that using DDA, a precursor is identified and then broken down into its fragments.  If so, how can the sum of the m/z of the fragments be so much larger than the precursor m/z?  If the fragments are not independent, how does the mass spec make multiple reads of the same fragment?  Is there actually multiple precursors with the exact same m/z value generating all of those fragments?

Thanks in advance.

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