Is this how stock dilution works? I bought 0.01 in stock and was able to sell for 3.81

Did Robinhood make a mistake? Or I got rewarded as an old investor for reverse split? I didn’t buy this stock because I like them, but just to see it crumble and would occasionally buy puts on it. I recently noticed that I had 1 full share and was able to sell it for 3.81$ even though the stock is down 99% over the time period. The only thing that changed is stock split. It also weirdly showed me that my cost basis was \~769?! But I can’t find it on the app anymore. The trades don’t appear on my realized profits/ losses but does appear for trade confirmation. Which leads to my initial question, did I accidentally make 3,830% return? Or am I missing something.