Diablo 4 Season 5 has a game-breaking bug that's reportedly awarding players up to 400 million XP for a single kill, and it could be all the Rogue's fault

gamesradar.com:

Diablo 4 players are flocking to Strongholds at the start of Season 5 in the hopes that a game-smashing bug might yield them almost 40 million XP in a single drop.

Shortly after Diablo 4 Season 5 dropped last night, Reddit user Neamins popped into the game's subreddit to share their kill of Stronghold boss Nilcar, Forgotten Bishop. Initially, it looks like a pretty standard fight, until Nilcar falls and Neamins finds themselves launched all the way from level 29 to level 63.

For those of you keeping score at home, that's an instant jump of 34 levels. It's tricky to get an exact sense of how much XP that means, but Neamins goes from about 90% of the way to level 30 all the way up to about 80% of the way to level 64. With the help of this experience-per-level tracker, I reckon that Forgotten Bishop Nilcar rewarded Neamins with somewhere in the region of 38.5 million XP.

Neamins isn't the only player who's found a massive XP drop so far this season. The replies beneath their post feature several others who've made substantial jumps; one player shows themselves going from level 56 to 82, a leap of 175 million XP; another says they went from 72 all the way to max level, at an astounding 407 million XP.

Understandably, several players are trying to replicate those rewards, but it's not proving that easy. Some have flocked straight to the Strongholds, while others have tried to replicate Neamins exact situation as closely as possible, but the results seem mixed; one player reports their massive dropped appeared at a different Stronghold, while another claims that theirs appeared during an Infernal Horde. 

The only thread that appears to be tying the drops together is the Rogue. Pretty much every report of a massive XP reward is accompanied by confirmation that the player in question was playing Rogue when they got their reward, suggesting that there could be something about the class that's triggering this error. Either way, it seems unlikely that this bug is long for this