When using Select All, the children are selected as well. When you move the actors, the children begin to move at different rates than the rest of the actors, resulting in them being offset when you're done moving. This also occurs when selecting the parent and their children, so it's not directly tied to the Select All feature.
This did NOT occur in //UE4/Release-4.25 @ CL 14469661, so marking as a Regression.
The children actors have their relative location changed by the move tool, making them offset from the parent
The children actors would maintain their location relative to their parent as they are moved
There's no existing public thread on this issue, so head over to AnswerHub just mention UE-108247 in the post.