Xiphos does not display words of Christ correctly in some modules.
Check Matthew 3 in the HNV - only part of verse 15 should be redletter, but it continues right to the end (including the title for Matthew 4, and Matthew 4:1).
Move to chapter 4 and Matthew 4:1 now isn't red, but almost the entire chapter is, when it shouldn't be.
Move to chapter 5 and most of the chapter isn't red, even though it should be!
I don't really know if the issue is really with xiphos rather than sword, but the HNV module does display correctly in bibletime and swordweb, although the ABU doesn't display redletter correctly in either xiphos or bibletime...