That's not unexpected. It depends on whether the xPDOTransport::UPDATE_OBJECT variable is set to true or not in the transport package. I wouldn't be surprised if packages created with PackMan are set that way.
Most extras use fairly specific names for the chunks. I usually prefix my own chunk names with 'My" to make them easier to identify and prevent what happened to you.
What was the package (hoping it was not one of mine)?
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