Breastmilk color

I am exclusively pumping for my son who is almost 5 months old. I noticed the other day that a couple of my bottles of expressed breastmilk were yellower than the others. Not like colostrum yellow, just yellower then the typical creamy white. I’ve read that that can happen when you or your baby are sick, but neither of us are, as far as I know. I feel like I may be starting with a UTI and he’s had terrible gas and mucus-y poop lately (he has untreated acid reflux and possible dairy intolerance, but not sure yet), but would any of that affect my milk just randomly? I’ve had mostly normal colored pumps besides those few. It smells and tastes okay and he drank it fine, it’s just weird.