Ï†Î·Î¼Î¹... has enclitic forms in the present active indicative (except 2nd sing. Ï†Î·Ï‚).
But on page 271, in the excerpt from Plato (Gorgias 456a-c), a sentence begins:
fhmi\ de\ kai\ ei)s po/lin...
Why is Ï†Î·Î¼Î¹ accented on the ultima? Is it because it's at the beginning of the sentence? Mastronarde mentioned this behavior with ÎµÎ¹Î¼Î¹ (be) but never with Ï†Î·Î¼Î¹ as I recall.