[The SOL headword here, mistakenly, is the secondary one in the entry.]
Forms with alpha from the aorist ei)=pon occur as early as Homer; "the 2nd persons indicative and imperative of this form are preferred in Attic" (LSJ s.v.).
[1] The gloss is considerably less common than the headword.
[2] Perhaps the lexicographer intended to say "also ei)=pon instead of ei)pe/," as at epsiloniota 173.