What does this long sentence mean and what kind of structure does it have?

Question

Repetitive, pulse-driven figures have remained a characteristic, but so have the slips and leaps of a lively mind.

'but so have (...)' part of the sentence confuses me a lot. Does the verb 'remain' affect the part after the second comma or not? How do I determine this? I comprehended the sentence in two slightly different ways:

1. Repetitive, pulse-driven figures have remained a characteristic, but they also have remained the slips and leaps of a lively mind.
2. Repetitive, pulse-driven figures have remained a characteristic, but they also have had the quality of slips and leaps of a lively mind.

I don't understand the structure of this long sentence; thus, I don't understand the meaning.

The source (requires a subscription and/or institutional login): https://doi.org/10.1093/omo/9781561592630.013.90000334653

For the people who don't have an access to the article:

Answer 1

The first comma is to separate elements of a list. The second comma is separating two independent clauses. See this thread.

You can rephrase the sentence to see the structure better:

A, B and C have remained characteristic, but so have D, E and F.

The sentence says that the artist's music developed over time without abandoning the underlying core principles. The music still has the characteristic repetitive and pulse-driven figures it originally did, but it also still displays the "slips and leaps of a lively mind", whatever that means.

"slips and leaps of a lively mind" could mean dynamic evolution, reinvention or freshness but that is not clearly explained in the provided excerpt.