If it's a "little bit gray", then you probably shouldn't sue for defamation about it.
The "breach"/"something-else-that's-not-a-breach" debate from what I've seen doesn't hinge on Facebook knowing or not, it's about if all loss of data can be called a breach or if the term should be reserved for cases where the perpetrator did aquire the data without Facebook knowing.
The "breach"/"something-else-that's-not-a-breach" debate from what I've seen doesn't hinge on Facebook knowing or not, it's about if all loss of data can be called a breach or if the term should be reserved for cases where the perpetrator did aquire the data without Facebook knowing.