Game crash when any video must be displayed if crossfade=true

[danorf69]

Playin the CD Original European Version (En/Fr/De) of the game,
with Scummvm 2.5.0
on Win10 (21H1)

if crossfade option is set to true (crossfade=true in scummvm.ini), the game crash when dragon3.fla must be displayed.

Error :

"Assertion failed: format.bytesPerPixel == 2

format.bytesPerPixel == 3

format.bytesPerPixel == 4, file graphics/managed_surface.cpp, line 321"

if the scene is skipped by pressing "Esc" before, the game continue to the main menu, but crash when trying to display the next video.

The game run with no problem if crossfade is set to false.