Can babies develop a sensitivity to formula?

My son has been formula fed since he was 6 weeks old (he’ll be 6 months old this week), we usually feed him the generic brand of gentle formula, though sometimes he gets Enfamil or Similac. He’s never had an issue with switching between brands.

I just opened a new can of Parent’s Choice which he has been on before, but it’s been a little while since then. The past couple of days after feeding him he’s been throwing up after every bottle. He’s been on Zantac for reflux for probably 3 months now which has helped him tremendously, but this doesn’t look like his usual spit up (it’s thicker and more than usual).

Is it possible that he’s developed a sensitivity to this formula? Or does it sound like his reflux medicine isn’t working as well? He’s been a bit cranky from teething, but pretty happy otherwise and no fever. Though sometimes when he spits/throws up he seems to be in discomfort.

Any advice is appreciated, I plan on calling his doctor if it continues for peace of mind, but I wonder if anyone else has been in the same position.