yes is only for mugen 1.1
do not understand why that happens in mugen 1.0 if prior to the stages in the same way, but not in hd and it did not happen :/
That because how you enable the Transparency (Trans) at the DEF.
see....
You have the RGB animations as this:
Spoiler, click to toggle visibilty
[BG 1 R]
type =anim
actionno = 1
start = -5, 420
delta = 1,1
[BG 1 G]
type =anim
actionno = 2
start = -5, 420
delta = 1,1
trans = add
[BG 1 B]
type =anim
actionno = 3
start = -5, 420
delta = 1,1
trans = add
Animations:
[Begin Action 1]
1,0, 0,0, 4
1,1, 0,0, 3
[Begin Action 2]
2,0, 0,0, 4
2,1, 0,0, 3
[Begin Action 3]
3,0, 0,0, 4
3,1, 0,0, 3
^this way only works at Mugen 1.1
To make it work at Mugen 1.0 should go like this:
Spoiler, click to toggle visibilty
[BG 1 R]
type =anim
actionno = 1
start = -5, 420
delta = 1,1
[BG 1 G]
type =anim
actionno = 2
start = -5, 420
delta = 1,1
;trans = add < As you see i disabled the Trans from here since doesnt work on Mugen 1.0
[BG 1 B]
type =anim
actionno = 3
start = -5, 420
delta = 1,1
;trans = add < As you see i disabled the Trans from here since doesnt work on Mugen 1.0
Animations:
[Begin Action 1]
1,0, 0,0, 4
1,1, 0,0, 3 <Keep the 1st set as it is dont touch.
[Begin Action 2]
2,0, 0,0, 4,,AS256D256 <These extra numbers "AS256D256" are how the Transparency works for mugen 1.0 animations.
2,1, 0,0, 3,,AS256D256
[Begin Action 3]
3,0, 0,0, 4,,AS256D256
3,1, 0,0, 3,,AS256D256
^Doing this to all RGB animations will make it display correctly at Mugen 1.0 with no issue.
I already did this to the copy i downloaded so as you can see:

Works fine at Mugen 1.0 now.