I hear the ll as ʝ in "Medellín" and ʎ in "mejilla".
It is on the first minute of these clips:
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I don't hear [ʎ] in either of the videos. I hear a voiced fricative [ʝ] in "mejillas" (which tends to become an approximant [j]) for the first few speakers in the second video (who are... Colombian?).
For "Medellín", the speaker (which speaks standard European Spanish) alternates between a fricative that sounds very close to [ʒ] and its corresponding affricate [dʒ]. I believe this alternation is common, especially when the syllable is stressed.
The sound transcribed as ll is only rarely a true palatal lateral, and it varies a lot among dialects and even among individuals. Since there are no similar sounds in Spanish that could be mistaken for it, this variation often goes unnoticed.
I can't watch the videos, but I speculate that, if the speaker(s?) is from Colombia, they may have a native language other than Spanish in which the [ʎ] is used, so they have that phoneme when they speak Spanish (this can be observed in native speakers of Quechua, for example); however Medellín is pronounced /Mede'dʒin/ even by foreigners who know little to no Spanish -- it's just the usual, common (and local) pronunciation.