Source has some code that causes it to load the page 1 content again on page 2. It’s a source quirk, the result of not all of the content that “should” be on page 1 of the homepage possibly not being shown due to lots of separate #get requests to make that layout. (Are you confused yet? Source is definitely confusing.)
But… it shouldn’t be loading the content repeatedly (just once, on page 2), unless you’ve got some modifications or unexpected interactions gong on.
I haven’t seen similar behavior with other themes.