Realmente existe a possibilidade da omissão do "k" ou meus ouvidos ainda não estão apurados o suficiente?
Sim, existe a possibilidade da omissão do 'k'. Observe o comentário a seguir, que explica este caso.
The pronunciation of "asked
" is actually very difficult because it contains three consecutive consonants articulated in different parts of the oral tract. You bounce from [s] at the front of the mouth to [k] at the back and back to [t] at the front again.
(The final sound is actually [t] and not [d]. These sounds are identical except that [d] is "voiced" (the vocal cords vibrate) while [t] is "voiceless" or "unvoiced" (the vocal cords do not vibrate). Since the [s] and [k] are also voiceless, there is a strong tendency not to voice the following [d], a process called progressive assimilation.)
There is a natural tendency for some speakers to simplify such clusters by dropping sounds; in this case you sometimes hear people drop the middle consonant, [k],
which makes pronunciation markedly easier because the [s] and [t] have exactly the same place of articulation: [æst]