Graveaxis, sorry to hear and thank you for posting your video.
Yes, "under load" is important information and I modified the title to reflect that.
What year and how many miles does your car have?
I note that the outside temperature was 32°F at the time you took the video.
Totally agree with kiev's assessment and simple first step to address the issue.
An app which shows cell voltage is the primary tool you need to diagnose this problem.
As a side note, it is disturbing that the dealer's first (kneejerk) reaction was to want to change the OBC/dc-dc ... this perhaps becoming the most common i-MiEV failure?