I did my own little research and bumped into the following threads. This seems to be a common issue raised frequently for various other brands and laptops. These threads suggest 2 problems: It could be either a problem with the PSU, or it could be an issue where the system doesn’t boot up properly due to low temperature. If its a problem with the PSU, then its a hardware problem and we cannot do much about that. But its a problem due to low temperature during boot, then I guess it can be fixed in BIOS. And we are also sure that this had been fixed earlier in BIOS v 0.22.
https://www.dell.com/community/Windows-General/Black-screen-when-cold-booting/td-p/4165065
I found a little work around to boot the notebook properly. What I am usually doing is that, I plug in the charger for 2 to 3 minutes, to increase the temperature and then use the power key to turn on the notebook and it worked on couple of instances where I try to wake the system from long sleep periods and while performing a cold boot after a long period as well.
Please try this and let me know if this works for you guys. Until GPD acknowledges the problem.