I just encounter a situation where I am not sure it is a bug or not. After I dredge Sunken Vessel with Trawler and play Edwin. Edwin draws Sunken Vessel and it cast itself, and the next card is drawn, the problem is after I played the new drawn card Edwin neither draws me another card or gain stats. I don’t think it suppose to work this way. Should Edwin gain the stats and draw me another card? Because sunken vessel cast when draw but I also played the next card.
The outcome you experienced is working correctly.
Edwin, Defias Kingpin puts an enchantment on the drawn card to cause its Battlecry effect to work. The Cast When Drawn card gets the Edwin, Defias Kingpin enchantment and does its cast and as a secondary effect draws a replacement card for your. That replacement card does not inherit the Edwin, Defias Kingpin effect.