https://dcemulation.org/?title=OpenBORManual#Palette
IF you look there you will see this:
palette {path}
~This is to set default palette for this entity. ONLY compatible with truecolor mode (see video.txt above)!.
~{path} is the location of the image whose palette will be used as default palette. The {path} is relative to OpenBoR.
~If truecolor mode is set but this command is not declared, the 1st image/frame of the entity will be used instead.
~Usually used in conjunction with 'alternatepal' below. But sometimes it can be used to change default palette entity is using
~If path is set to none, alternate palettes are ignored and allows each frame (see 'frame' in animation data below) to use its own palette
~Useful to create effect libraries without having to design public palette for all of those effects
This is the part that I think you need to see: If truecolor mode is set but this command is not declared, the 1st image/frame of the entity will be used instead.
So you need to look at the 1st image/frame of the entity and see if its palette is the right one for the rest of the frames.
That's my best Guess.