[Issue?] Two tilesets, one palette?

[System64]

Hi,
I did this code : 

Code:

#include "includes/Tilengine.h"
#include <stdio.h>

int main()
{
    TLN_Tilemap tilemap = TLN_LoadTilemap("assets/floor/floor-tilemap.tmx", "floor");
    TLN_Init (400, 240, 1, 0, 0);
    TLN_SetLayerTilemap (0, tilemap);

    TLN_CreateWindow (NULL, 0);
    while (TLN_ProcessWindow()) {
        TLN_DrawFrame (0);
    }
    return 0;
}

Or the simplest Tilengine exemple you can do.

The tilemap uses 2 tilesets, each has its PNG file. But seems both tilesets use the same palette from the first tileset instead of each tileset having its own palette. Is it normal? Did I forgot to do something? Thanks for your answer!
Also please note my PNGs use indexed colors, and I also use Tilengine v2.11.3 64-bit and Tiled 1.9.2.