Trouble keeping d-beat tight at higher tempos (kick desync)

Hi all, When I play d-beat at faster tempos (around 170 BPM and above), the spacing between the first snare and the following kick becomes inconsistent. The second kick often ends up too close to the first snare:

        1 + 2 + 3 + 4 +
            S       S  
        K   K     K    

Sometimes the kick even shifts slightly before the snare:

        1 + 2 + 3 + 4 +
            S       S  
        K  K      K  

I experience this both with and without a metronome. At higher tempos it becomes difficult to control the small gap between the snare and kick.

Do you have any advice or exercises that help keep this subdivision stable at faster speeds?

Thanks!