Faint musical patterns

[Thermospore]

Am I going crazy or is there music playing very quietly in the background of the brown noise?

It's very faint, but I often clearly hear repeating musical patterns and melodies in the background. Usually I play the noise on my phone speaker while I sleep; the musical patterns are easier to hear in some places in the room than others (due to the way the sound reverberates / filters within the room)

It's not a different app or external noise; I've narrowed it down to this app

The pattern seems to be different each night. Some nights I don't really hear one

Might be an unintentional effect due to how the noise is generated