vbNewLine works sporadically

[JosephHawkes]

I've been using vbNewLine to label features with ArcMap 10.5.1 and have found that sometimes it will display correctly, then later in the same map will no longer split the label on two lines.  An example of my expression is below:

[Field1] & " ft" & vbNewLine & [Field2] & " year"

Has anyone else experienced this sporadic problem or found the reason/solution?  Thanks. 

[JosephHawkes]

I think my issue might have been in the Placement Properties Line Settings with the Orientation of the label as curved.  When I change the Orientation to Parallel the two line label appears correctly.