We Built This City [On Rock an' Roll]

https://gifer.com/en/BkdU

what's going on with the timing in the chorus? why does the second part of the refrain seem to slam into the first in a hilariously awkward way?

This is the most clever bit in the song! They knew that it would be redundant to say the entire phrase "We built this city" four times in a row, so the third time they just say "built this city", but they sing "built" on the offbeat before the one where they usually sing "we", which keeps the chorus rolling nicely.

...before the one beat, that is.