We have one board with two different CPU versions. One is i.MX6 Solo and the other is i.MX6 DL. The CPU reset wiring is completely the same as it is on SabreSD board. Now we use the CPU reset key to power off board as our production version. Unfortunately after we ship our products to the field, we found out the Solo version demonstrate different characteristics. Based on the CPU datasheet, supposedly the board needs to be shut off after 5 seconds. However, we do find a percentage of these boards can be shut off within a second or two. However, DL version does follow the datasheet to shut off after 5 seconds. Is this a CPU problem?