While the idea of a "lost" or "banned" episode can be an intriguing mystery, the specific search for "lost panties" in The Loud House does not correlate with any real production history or aired content. It is almost certainly a product of internet folklore or fan-made "shock" content designed to provoke a reaction.
Much like the famous "Squidward’s Suicide" (SpongeBob) or "Dead Bart" (The Simpsons) stories, internet users often write horror stories about "lost episodes" that contain disturbing or inappropriate imagery. These are works of fiction intended to unsettle the reader. the loud house lost panties new
If you are looking for legitimate updates on new Loud House content, it is best to stick to official sources: While the idea of a "lost" or "banned"