The one problem i have with the advice is with the fans, only because they will be commanded to run based on the inverter temperatures and OBCM temperatures, and if they are heat soaked due to extended use or high ambient temperatures, they need to run to get the coolant temp down. what complicates this, is that there is a valve controlling coolant flow into the OBCM (On Board Charge Module) that got mis-wired on some early cars. what is supposed to happen is that the OBCM would get warm, the valve would be commanded open and coolant will circulate, cooling the module. if the coolant gets too warm, the fans are commanded on to bring the temperature back down. On some early cars, the valve got wired backwards, and so instead of opening, it closes. the OBCM continues to get warm and the fans get commanded on. Eventually the OBCM gets too warm and shuts down and you end up with an incomplete charge.
Now what the going to sleep before charging, or after charging thing does is different. the OBCM communicates with other modules to facilitate charging, including the Hybrid module and Battery Module. By allowing the car to goto sleep first, you are making sure the data bus lines are clear and all modules have shut down properly. When the OBCM detects an outside charger being plugged in, it wakes up the Vehicle Control Module to have the other modules it needs to talk to to be woken up (IE the BECM to unlock the HV system). becuase it deals with HV, the OBCM is a finnicky bastard, so if somehting isn't right, it won't charge. Now it maybe something as too much resistance in the charger detection circuit, but it may also be something such as it doesn't recieve the expected responce from the BECM or HCM. Either way it says i see a problem, i am not doing this anymore, get it fixed. the BECM sees that and then triggers a CEL/MIL.
AT this point the checksum error DTC is a 100% software glitch (a portion of the bootloader is corrupted in the BECM) that can only be fixed with an engineering re-flash right now, but it does actually fix that problem. i know surprising. Doesn't matter what you do in terms of letting it goto sleep or not, you won't affect this, nor induce it.
The letting everything go to sleep and not openning a door thing HOWEVER does affect the OBCM communication codes that cause the BECM to report an issue, triggering a CEL/MIL. Which is why at the minimum, don't awaken the car while it's charging.