Anyone have any issues with baby preferring one side so much that they are pretty much only eating from that side? I try…

Anyone have any issues with baby preferring one side so much that they are pretty much only eating from that side? I try the smaller side every now and then but he gags on it.. i was so confused as to why it made him gag considering it has less of let down. So I decided to taste it and realized the smaller side had a salty sour kind of taste when the side he often feeds from was sweet. I have no signs of mastitis so the only thing I can figure (after reading everything I have) is that the taste is caused from my body thinking he's weaning from that side. Anyone notice salty breastmilk when weaning? Is it possible for your body to think you're weaning only one breast? This is all so confusing!