First of all, let's correct the audio: Karájuka mumtáz yá bob. The speaker spelled (J) as (ZH) - typical. Also, it should be Karájuka simply because it is a subject (nominative case).
The (-a) you hear after (karájuk) normal and it should be so; It is part of the possessive suffix (-ka) "your/m". The feminine counterpart is (-ki).
Typically the final sound disappears when it comes at the end of the sentence, and the word could be spelled : karájuk; This is in the case of the masculine suffix. The feminine ending (-ki) is typically not shortened to make it, let's say, more elaborate that a female is spoken to.
In modern dialects, specifically in the Levant and Egypt, the vowel in these 2 suffixes is flipped back, becoming (-ak) and (-ik) for the masculine and the feminine respectively.