has been bobbling
Presente perfecto progresivo para el sujetohe/shedel verbobobble.

bobble

One aspect of his talk has been bobbling around in my head ever since, and it's this aspect that I'd like to explore further in this post.
Uno de los aspectos de su discurso ha sido bobbling vueltas en la cabeza desde entonces, y es este aspecto que me gustaría explorar más a fondo en este post.
Palabra del día
el guion