As you can see, the panel is 128x128, the edges are bugged, do you know any way to fix it without making an instance from scratch?
Light bug
As you can see, the panel is 128x128, the edges are bugged, do you know any way to fix it without making an instance from scratch?
I've had it happen to me several times, but I don't know any fix for it yet.
Have you tried doing a full compile and checking if the bug still happens?
And btw, you don't really need to make a new instance from scratch, just open the one you're currently using into Hammer and hit the "Edit Instance" button, after you're done editing it "save it as..." a different name 
Always full compiling.
@josepezdj
It is set to NO by default...
And the edit instance is what I am using exactly.
Follow Lizard's advice, compiling FULL usually solve many lighting issues...
Hmm... I can't remember clearly, and I'm not in front of my computer to check it, but if there's an arm model under the panel in that instance, maybe is causing some shadowing on the panel... so you can try disabling the shadows for the arm model: Disable Shadows = YES.
It also looks like it may be a different texture above that panel too(I see three different white floors like that when I search it up), or at the very least, the texture isn't lined up with the tiles around it. Id say your best bet would be to make it a different texture and see how that works? Maybe test what happens when you use the black metal floor texture.
1: check the animations of the arm and see if you can tweak the setup to have the initial position to be how you want it to look. This would create the problem again after it moves, so it's only good for if you are trying to get it to blend in more while it is closed.
2: Place another light at a similar displacement at each idle animation point. so like place a light right in front of where it is when folded up/down, and another above it for when it's against the ground like the picture shows.
3: My favorite cover-up for this problem is to place a projected texture over the object with the lighting issues. If you are trying to use the PTI, just place an office window right next to it. If it's a destroyed map, a good skylight over it would work well if you are not using something like that to telegraph something else in the map. Making it dark in the area, and giving the player a flashlight is another good workaround if it fit's the atmosphere.
1. the initial position of the panel is facing like in the image, when I activate it, the lighting seems to be better, but not perfect, I suppose this isn't the problem
2. Didn't try it yet, but sounds promising.
3. env_projectedtexture for a reason that I know but can't fix, doesn't work in my map (which is OK because real sunlight is the most realistic with light_environment because it has good divded shadows while env_projectedtexture the shadows arent divided correctly).