The issue appears to be unique to Southwest, which handles in-flight beverages differently than other airlines. It does its own provisioning and doesn’t handle

The issue appears to be unique to Southwest, which handles in-flight beverages differently than other airlines. It does its own provisioning and doesn’t handle perishables, since it does not serve meals during flights. The company is now testing out trucks with air-conditioned cargo areas in Phoenix and Las Vegas. From TFA. That is: Southwest handles its own catering and uses un-chilled ground transport. The cans are getting hot on the ground, probably before being loaded onto aircraft, and burst as cabin pressure falls during ascent.