The line if( subgrid_integration_active ) start_tree = create_shape_fcn_tree( ls->Integration_Depth );

Tries to create a shape fcn tree (still unsure on how this tree structure is meant to behave). but in some cases the ei structure is not set correctly which the create_shape_fcn_tree uses to malloc structures inside the tree.

When the ei is not set correctly then the arrays in the tree are not malloc'd and then goma tries to read and write to the unmalloc'd space causing segfaults.