So, what's the explanation for the infamous "Maclunky/Maclanky/Maclanka" loop that Vinny Vinesauce ran into?

Anyone who follows Vinesauce streams should know by now that recently Vinny streamed AI Dungeon and after some time encountered an endless loop which has already become both a meme AND a hated copypasta in the community.

Here's a clip of part of the insanity: https://clips.twitch.tv/SlickAntsyYakResidentSleeper

I was wondering how the hell this kept happening, that this one response kept getting returned verbatim after multiple different prompts. Is there something in the AI that broke and made the engine return that text by default after every prompt?