Like many guitarists I'm not great at reading traditional music notation. I just came across the following bar, and I'm confused:
(If anyone cares, this is from the song Sequoia Throne by Protest the Hero. It's from the official transcription published by the band; it's not just some random unreliable tab from the internet.)
As far as I can tell from listening to the track, every note in this bar is supposed to be of the same duration, and in fact that's the only way to make the notes and the rest "add up" to an exact four beats.
So why do some groupings of notes have a "3" written above/below them while others have a "6", when each grouping only has three notes in it? Is it even permissible to write a "6" like this above a grouping of 3 notes?
I suspect that this is a typographical error but I'm not confident in my own knowledge of music notation. Am I missing something?
(I know what triplets and sextuplets are; my question here is about the notation.)