A poster in the Apple Support Communities has pointed out that the fonts Devanagari MT and Devanagari Sangam used for OS X and iOS produce the wrong glyph for the sequence ph + virama + n.
Note: Not fixed in 10.9
Info on a separate bug for the sequence r + virama + h was reported here.
Note: Not fixed in 10.9
Info on a separate bug for the sequence r + virama + h was reported here.