Dynamics don't work when another is across a barline in playback, need help.

I'm making a piece where there is a group of measures where the trumpets play a whole note, starting at a quiet pianissimo dynamic before rising to a very loud fortisimo at the end of the whole note, then going back to the quiet pianissimo at the start of the next measure like the last one and doing the same thing again. For some reason in playback, though, the dynamic of the fortisimo at the end of the last measure carries through the barline to the next measure, even though there is a pianissimo dynamic under the next measures whole note. Is there any way to combat this, or is it a bug that isn't fixable?

Below is a picture of the notation I described above.