Milk in Japan sometimes has a weird burnt aftertaste?

I make a lot of lattes and I’ve noticed that in the summertime, sometimes milk has this strange aftertaste that I can’t really put my finger on. Almost like caramel, but in a bad way? I’ve noticed it in different cities in Japan and with different grocery stores and brands, but never in my home country or anywhere I’ve traveled to.

Has anyone else noticed this and figured out how to avoid it? I know Japan tends to use pretty high heat pasteurization so I wondered if that might be related ….