HB thermal load balance - electric equipment load is normalized by incorrect floor area when applying natural ventilation for part of those rooms

Hi LBT community,
I’m using Ladybug Tools v1.5, and I experienced a strange result using load balance. When I apply HB window opening component to some of the rooms (not all rooms), I found that electric equipment load is normalized by the floor area of the rooms that have natural ventilation only instead of the total floor area.
I create a 2 floor building with the room size of 5mx5m.
Group A, 1 room has natural ventilation
Group B, no natural ventilation
All other parameters are the same.
The result is the same for group A and B in the output of “balance” but it is different in “norm_bal”.
The image below may explain better. The result is for 1 month.

In fact, just conncet and disconnect the “nat_vent_load” can show the difference.
Dear @chris and @mostapha , is it something wrong with my process? Really appreciate your helps!

Thank you!