In a similar vein, sometimes my breath feels sort of ‘milky’, even though I haven’t eaten any dairy products. What could that be?

Edit: Apparently this is not normal??
Try this experiment to see if you get the taste as well:
Next time it’s freezing outside, sprint for a bit so that you’re left taking deep breaths in the cold air by the end of it. That’s when I get the taste. My saliva also feels a bit thicker, probably due to the cold air.