T4,
Then the pods that you have seem not to electrically match with your Mac, as the others that you tried seemed ok, am I right in this understanding?
On the iPhone it has a very unique plug configuration that seems to set specifically for the iPhone, because it is a 4 conductor connector (one is for the microphone) that may make other pods not work properly. (yes this is an Apple thing, AAAAARRRRGGGG!!!!)
But that would then confirm that there is not anything wrong with your Mac, as those Apple pods are for the iPhone, I guess both good and bad news.
I don't use my iPhone to listen to music, nor do I use pods either, unless the artist I am working with is, then I use the same make and model so I can "hear what they hear".
I do pro audio for a living and I can understand this "crosstalk issue with the 4th connector"
But without getting too technical, it would seem your Mac is just fine, which is a good thing.
I would think that the newer Macs will be more compatible with the Apple iPhone pods, but they all seem to have their issues with the switching system...for years now!
Hope this helps you understand this "FRUIT FLY"
My suggestion is to use "regular headphones/ear pods with your Mac and the Apple iPhone pods with the phone. )I only have ever used the iPhone pods with the iPhone when I'm driving, and with only the iPhone. I have much better sounding pods/phones that I use to "ACTUALLY' listen to music with....and it a'int MP3/4
Peace SJP