@djwfyi Before or after the beat? It could be an issue of delayed or premature beat recognition. In other words, in anticipation of where the beat should be, your child could be hitting either early or late or both.
Instead, try having your child verbally count out the beat and clap. “Clap, one, two, three, clap, one, two, three, clap, one, two, three, clap“ and so on without the metronome.