Launcher unable to read mod files

[viciscat]

Frick i'm starting to feel like i'm annoying
So here's the situation, when I try to launch my modpack with the fancy-launcher, it only launches with forge and no mods, because apparently it can't read the jar files of the mods. Here's an exemple

[22:41:39] [main/ERROR]: Unable to read the jar file BetterFps-1.4.8.jar - ignoring
java.util.zip.ZipException: invalid END header (bad central directory offset)
	at java.util.zip.ZipFile.open(Native Method) ~[?:1.8.0_301]
	at java.util.zip.ZipFile.<init>(Unknown Source) ~[?:1.8.0_301]
	at java.util.zip.ZipFile.<init>(Unknown Source) ~[?:1.8.0_301]
	at java.util.jar.JarFile.<init>(Unknown Source) ~[?:1.8.0_301]
	at java.util.jar.JarFile.<init>(Unknown Source) ~[?:1.8.0_301]
	at net.minecraftforge.fml.relauncher.libraries.LibraryManager.extractPacked(LibraryManager.java:200) [forge-1.12.2-14.23.5.2855.jar:?]
	at net.minecraftforge.fml.relauncher.libraries.LibraryManager.cleanDirectory(LibraryManager.java:169) [forge-1.12.2-14.23.5.2855.jar:?]
	at net.minecraftforge.fml.relauncher.libraries.LibraryManager.setup(LibraryManager.java:97) [forge-1.12.2-14.23.5.2855.jar:?]
	at net.minecraftforge.fml.relauncher.FMLLaunchHandler.setupHome(FMLLaunchHandler.java:106) [forge-1.12.2-14.23.5.2855.jar:?]
	at net.minecraftforge.fml.relauncher.FMLLaunchHandler.setupClient(FMLLaunchHandler.java:81) [forge-1.12.2-14.23.5.2855.jar:?]
	at net.minecraftforge.fml.relauncher.FMLLaunchHandler.configureForClientLaunch(FMLLaunchHandler.java:42) [forge-1.12.2-14.23.5.2855.jar:?]
	at net.minecraftforge.fml.common.launcher.FMLTweaker.injectIntoClassLoader(FMLTweaker.java:141) [forge-1.12.2-14.23.5.2855.jar:?]
	at net.minecraft.launchwrapper.Launch.launch(Launch.java:115) [launchwrapper-1.12.jar:?]
	at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]

But when i test using the modpack creator tool it works just fine with all the mods so there's 2 suspects.

1. My website corrupting the files
2. Modpack creator tools building the modpack wrong or the launcher reading it wrong.