I also tested diMka and GJA skins and the issue fixes as you envisioned. So at this point, I can confirm it looks like a bug as you mentioned.
In DATA.ZIP/project_config/igo9.ini, I ran into these lines:
================
[interface]
skin="ui_igo9"
newalignment=1
bilang_city=1
enable_stateanim=1
builtin_themes="SKIN~Default - night|skin_night,SKIN~Picto|default_picto,SKIN~Picto Night|default_picto_night"
resultsinqueryorder=1
use_autohint=0
font_quality="light"
show_tutorial=1
use_dual_names=0
theme_night="skin_night"
=================
Do you think playing with this section helps?
Also in DATA.ZIP under ui_igo9\scheme\day\ there is a color.ini. It starts with:
[INFO]
name="COLORSCHEME~Default Day Colours"
night=0
default=1
preview=""
[color]
0="ground", 215,230,205, 1
a="0_int", 240,210,0
A="0_ext", 160,100,100
d="0_int", 240,210,0
D="0_ext", 160,100,100
c="1_int", 243,243,12
C="1_ext", 190,88,44
e="4_int", 243,243,12
E="4_ext", 190,88,44
g="5_int", 247,230,52
G="5_ext", 150,150,150
h="6_int", 255,235,128
H="6_ext", 180,180,0
i="8_int", 255,235,128
I="8_ext", 180,180,0
k="9_int", 255,255,128
K="9_ext", 180,180,0
l="10_int", 255,255,255
L="10_ext", 220,220,220
u="12_int", 248,248,248
U="12_ext", 235,235,235
r="freeway_int", 255,230,0
R="freeway_ext", 120,120,120
I think this is the array you are mentioning. Can you please shed a light regarding the logic of this array structure?
Thanks again!