playback dynamics issues

So this score i'm working on, specifically the piano part, has been acting wierd dynamics wise lately. The part plays really quietly (and the actual soundfont timbre sounds like a piano being softly played) for a measure, then goes to being very loud the next measure. I marked the part as piano (quiet) at the beggining, but it doesn't seem to carry over past the first measure. The only way that I have been able to fix it is by manually deleting and rewriting a chord. When I do this, the part plays softly as it should. I'd really like to avoid doing this for the whole score, and avoid this issue in the future. Does anyone have a solution?