null-stalgic

Nostalgia that isn't nostalgia to someone, and rather reminds some of personal nostalgia/ old things that gives them nostalgia of something that never existed in the first place, that often the person is heavily aware of, and happens for no apparent reason. The noun version of this is "Null-Stalgia"

"Wow, this music from the seventies is making me very nostalgic".

"But-"

"Its probably just fake, null-stalgic memories."

"Okay...".