Are these sliding fields? If you check preview versus printed does the text wrap to a new line at a different point?
If so, this is a known issue. For More Information see: FM 12 preview mode issue
This is one of many acknowledged bugs that can be found in the Known Bug List thread here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: https://www.dropbox.com/s/jt09b82i0xijbu3/FMP%20Bugs.zip