for quite some time, they've had 2 types of coil. the oil filled ones, which it says right on the package, "do not mount horizontally" because the oil will leak out of them, they'll overheat and breakdown.

the other was epoxy filled, or at least epoxy sealed on the top, and were noticeably more expensive, these were ok to mount in any position you wanted.

sure you can call them a poor design, or say that quality has gone downhill with a shift in manufacturing location, but it's kind of hard to put blame on anyone but yourself when they tell you right in the instructions "Do not mount horizontally" and you chose to mount it horizontally...