Problem with crescendos and decrescendos

Maybe badly anchored?
Better to attach the score,
Try to reposition https://musescore.org/en/handbook-notation/lines#apply_lines
or delete then select the start note, hold down Shift, right arrow to the note of arrival;
double-click the symbol in the palette

More specificvally, you probably used the "drag" method of extending the hairpin, which increases its physical length but doesn't change its logical attachment point. You probably extended it at a time when the next measure was on the same page and MuseScore dutifully recorded that physical length, but now that the next measure is on the next page that length no longer makes sense. That's why it is important not to make adjustments using physical length but instead the logical start and end points.