Acdelco alternator smells like burning
 

Hi everybody! Interesting case, I'm is boat mechanic and my cars I fixing by myself. So, I have Escalade 09 esv 120k miles. My alternator making a little noise to my stereo and when i checked voltage with my multimeter I found 13.2-15.1 volts. So, I monitored it last two days by oem voltmeter in the gauge panel and sometimes he holding on the 13 (on the highway). It's no good, also overcharge it's no good to. Anyway, I need to replace it. I found oem ACDelco alternator on the Amazon for $169. Hmm, it's cheap for 160amp I belive and I ordered one. Also I checked description on Amazon and it's not looking like refurbished, it's brand new! Next day I got one, I opened box for visual check and I can smells like burning wires from the alternator. Hmm. Maybe it's broken or something else. Ordered the replacement and get other one today (previous one I hold in the box in my truck to send it back) and this one smells SAME, like burning wires. Wth???
my question is - this is my paranoia or two of two new alternators burned?? Or it's ok? Maybe somebody haven same problem? I keep both in the boxes now for understanding situation. Thanks 😊

https://www.amazon.com/dp/B0016HYFPC/ref=cm_sw_r_apan_glt_fabc_T8RZMQSBP0MPMFNSXQ72?_en coding=UTF8&psc=1