Which OS X is on the 2015? I can't remember exactly when Apple started quarantining, but any chance those are just plugins that didn't make it past that? One easy way to know the quarantine status is to run the free PlugDeQuar ( from
https://pelennor.gumroad.com/l/djesj ) which tells you and then can dequarentine in one click.
Quarantined plugins *should* give a pop up alert but I've discovered that's not 100%.