but that’s how it works. japanese people recognize words instantly, while figuring out a kanji takes a moment, if the kanji itself is not a word on it’s own.
you can almost see them rummage through their memories 
and then, they remember it not as a single unit, they remember words it pops up in.
the reason is, they don’t learn kanji one by one after the first 2-3 years in school anymore. they learn words only. they’ll never encounter them standalone, so learning them like that wouldn’t make sense.
i think some people don’t know this and just trust that “koichi knows best”, while others are aware and try to be more japanese than the japanese.
learning them as single kanji is useful imo, but don’t beat yourself up for not recognizing them when they pop up with no context on a flashcard website.