Dive Deep into Creativity: Discover, Share, Inspire
Ok, so, recently I've been doing research on the different versions of Jason Todd and his life, death, and afterlife for reasons, and I stumbled across the discontinuity that is Jason's autopsy scar.
This post by pluckyredhead and this post by dailyjasontodd explain it pretty well, and when ruminating I realized that there is a perfect, literal explanation sitting in front of our faces.
Jason didn't have an "autopsy" if you mean someone performed postmortem surgery to try and find cause of death. That would have been impossible, since he most likely had a quick and quiet burial to hide his forensic ties to the Robin life.
No, what Jason had was experimental surgery done by the League of Assassins. I'm not an expert, but I think part of the reason Ra's al Ghul had an interest was because Jason came back to life for seemingly no reason. (and if that's not true based on current continuity or whatever, it's my personal headcanon anyway so)
Ra's wanted to figure out what made Jason live again. Part of that process would most undoubtedly include exploratory surgery that mimicked an autopsy, but didn't include permanent harm because they couldn't study what made him live if he was dead, right?
The scar is mostly fanon except for that one Robin variant cover, and most of the cause is to make Jason have more angst over his death and/or to freak out the rest of the Batfamily. But how much more angst would they, specifically Dick and Bruce, have when they realized that wait, Jason didn't have an autopsy, why does he have a scar, and then they find out that he has that Y-shaped scar because a secret league of assassins tried to cut him apart and dissect him to figure out how he was alive?
I don't think they would take that very well, to be honest. Especially if they found out that it was when Jason was catatonic, so no, there was no consent or anesthesia either. (and imagine the nightmares that Jason would have, not just of crawling out of his own grave and the Lazarus pit, but of being dissected alive and being able to do nothing to stop it)
TL;DR Jason Todd has a Y-shaped scar because the League of Assassins tried to dissect him, not because he had an autopsy in Gotham.