Alexander01998 pwerta114 Two questions: Is your Wurst installation up to date? (Don't just say yes, tell me your exact Wurst version and Minecraft version. This matters.) Is the server Cytooxien? (The usual suspect for using shady mod detection exploits.)
retegrity pwerta114 it could be the server abusing the sign translation exploit for other mods (accurateblockplacement, freecam, fast xp, or any other unfair mod that does not have protection against said exploit.)
Alexander01998 pwerta114 As @retegrity and @snowpelt737 said, other mods installed alongside Wurst or the Spoof Vanilla Option being enabled could cause the issue you're seeing. Wurst itself is not vulnerable to the sign translation exploit, it was among the first hacked clients to patch it.