It's not a reason to save or chuck just an observation. Like if you have 2 balloonsOhhhh, OK.....yeah, any 'floater' will do that, to varying extents
One you blow up by mouth and the other has helium. If you hold them under, they will both rise but the helium will run to the top (and keep going...)
The bottom line is that they should be opened in a separate dish before throwing into food.