SS commented on that. She said there was no visible lividity in the arms and upper legs, as well as the torso.
At the risk of being very graphic, was SS looking only at autopsy photos of Hae laying on her back or are there photos of Hae on her back, side and stomach? Who knows, but I have a hard time imagining no lividity anywhere but on her uppermost body and neck area? What position would not result in lividity below the upper chest? They can argue all day long that the lividity is not consistent with a "side" burial, but it also is not consistent with their theory that Hae was laid prone somewhere for 8 hours prior to burial.
According to SS's blog, Hae had to be removed from the trunk no later than 4:30 and left somewhere for at least 8 hours before burial. So who agreed to keep a dead girl's body in their house, garage, basement, etc., and in what position was her body that no lividity formed on her stomach, legs, arms and feet?
Neither SS nor EP have even bothered to deal with the problem of rigor. By midnight, Hae's body would be into the advanced stages of rigor, possibly even full rigor. How was she moved from this unknown location and buried on her side if rigor had set in while she was in a prone position? I can only imagine that it would have been very challenging, not to mention very disturbing.
The fact always was and still remains that we don't have enough information about the grave and Hae's position in the grave to make a determination of when she was or wasn't buried.
If Hae's body was in a position similar to your graphic, and if the grave was dug unevenly, with the upper body in a downward slanting position, a 7 pm burial would be perfectly conceivable.
SS was asked in her AMA to describe Hae's body in the grave now that Rabia has given her everything Serial had, which includes photos of her body in the grave at the various stages of disinterment. SS choose not to answer that particular question.