‟錯乱(sakuran)” describes the state of being mentally disordered/confused. It’s more like a general confusion though – having no idea what goes on, having no idea what is real and what is not – when one has completely lost their mind.
Since the original version of this song (with ほたる as vocalist) was titled ‟錯錯乱乱”, it’s safe to say that the song is about that topic. When you look at it like that, I like how asahi chose the title of this remake. Only bare sensory perception is left (hearing, seeing) without nearer classification what goes “pit-a-pat” and what is “gleaming”.
I’d go a step further with my interpretation and claim this song is about dissociation/depersonalisation (being detached of immediate surroundings or your own physical and emotional experiences; in extreme cases it can lead to feeling like a doll, seeing things in front of oneself hundreds of meters away, things being out of proportion etc).