Is it possible that this field extends past the right hand edge of the layout?
It should wrap to the next line and be the same in Filemaker 12 and 13 and I can't think of any other way that this would behave as shown...
No, the field does not extend beyond the layout. It does wrap properly if I type in the words manually but if it "import" the data from the parent table, then it does not work. [works fine in FM 12]
Try this test:
Create a brand new layout.
Use the field tool (don't copy and paste from your first layout) to add the field shown to your layout.
Examine the text in this field.
Does it wrap correctly on this new layout?
Also, do you see this for all records where the text in a line exceeds the width of the field, just this one case, or just certain records?