The air is exhausting out the black fan. The software reported internal temps seem fine. So I'm guessing is just variance of the actual chips inside or difference in manufactured lots. I'm not sure of the internal design of these but I'm wondering if there is a heat sink or something inside that is in contact or transferring heat directly to the housing.
Unless you notice a large dent in the exterior casing your heatsink should be about 1 cm away from the casing. Your temps are in range, a little on the high side. I know that my miners are hot to the touch when they ran in the fall during the warmer weather. Once it got cold all my temps and fan speeds dropped and they became warm, the underside is still warmer.
Just keep an eye on the logs and the miners you should be fine.
