Had a quick sit down at piano and figured out what was going on harmonically:
Bass goes E -E an octave up- A
Chord over the top is probably Am.
So because chord is Am, key feels like Am too (even though it could be a different key, too few notes to tell really)
Therefore normally in Am first note of the headline is A, but in this case it's E, and it moves to A a bit later in the bar, which is why it feels resolved halfway through the bass pattern rather than at the beginning.
It's actually really, really simple music theory, but it's the kind of rule bending anyone who knows a lot of theory wouldn't think of, weirdly.