I don’t think this is the same issue as Gridfinity horizontal line at wall transition - #10 by dave.p because the deviated areas occurred at a specific height and sides.
The top one printed with Classic wall generator, bottom one is with Arachne wall generator. The opposite sides ( the rear and left side of the bed ) printed fine in both prints.
I’ve printed many similar shapes without issues. BTW, the wall thickness is even in the deviated areas. Any idea what could have caused this?