ekacīvaraka asthāt
instead of ekacīvarako 'sthāt
pṛṣṭa avyākṛtam instead of
pṛṣṭo 'vyākṛtam
I mean (in asya) the presence of the two consonants
following the initial
a, which lenghtens the syllabe, and makes
the initial
a pronounced long, resulting in the fact that the
final e here conforms with the "general"
rule (becoming a(y) when followed by any
vowel, except a, or
diphtongue).
Conversely, the two
consonants following a ā can
make it considered as short, as Renou notes ibid. with the
(mainly epic) occurrences of -o/-e 'tman
for -a ātman.