List of Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey glitches
From the Super Mario Wiki
This is a list of glitches in Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey.
Note: All names are conjectural unless otherwise specified.
Blow up Bomb Early Glitch
In the Tunnel, if the player correctly positions Bowser, his fire can go through the wall and blow up a bomb that creates a shortcut that the player is supposed to reach later on. If the player decides to try and go back to the area before the shortcut, they will get stuck because the wall has not been blown up yet. Bowser will eventually be teleported to the start of the Tunnel.
Lumbar Nook Warp Glitch
In Lumbar Nook before Bowser learns Spike ball, there's a small area where Mario and Luigi can dig into a layer of bone. When the player jumps out, the game will briefly freeze, and set Mario and Luigi to the start of the Lumbar Nook.
Mario Bowser Path Warp Glitch
There's a serect area at the front of Bowser's Castle on Bowser Path that only a small Mario can reach. In it, if the player jumps to an empty space in between the ground and a higher up area, Mario can get stuck. The game will quickly teleport both Mario and Luigi to the very start of Bowser Path. Mario will also be back at normal size again.
Peach's Castle Warp Glitch
In the bedroom area of Peach's Castle, if Bowser moves around on the left side of the bed, he can eventually be placed out of bounds. Afterwards, the game teleports Bowser to the very beginning of Peach's Castle.
Peach's Castle Teleport Skip
In the northern part of Peach's Castle, if Bowser goes into Spike ball and moves into a pipe near a loading zone, the game will freeze and place Bowser in the front room of Peach's Castle.
Peach's Castle Garden Warp Glitch
In the bottom right area of Peach's Castle Garden, if the player moves Mario and Luigi into the tower around the left side of the loading zone, the game will freeze and place Mario and Luigi at the start of Peach's Castle.
Toad Town Walk Through Wall Glitch
Incorrect Hammer Animation
When Mario uses his hammer to hit a button to begin the Shroob boss fight, Mario's hammer will hit the ground instead of the wall with the button. The button still counts as being hit though, allowing the player to still be able to fight the Shroobs.
Jumping Sound Effect on Menu Glitch
When the player switches from Bowser to Mario and Luigi, there's a brief chance where if they press , the jumping sound effect will play on the menu for Bowser's body, even though the player cannot jump on the menu.
No Music in Dimble Wood
When the player finishes the Giga Carrot minigame, and chooses to save after talking to Wiggler, switching to Mario and Luigi and then to Bowser will cause no music to play.
The player can fix this by entering any area.
If the player burns a Sneed and it goes into the ground to create a Flifit, the Flifit will freeze in place, and the game will softlock with the sound effect that plays during the process of the Sneed turning into a Flifit repeatedly playing.
Sniffle Thwomp Freeze
Sometimes, when the player fights a specific Sniffle Thwomp in Bowser's Castle, there is an unlikely chance that whether the player wins the battle or runs from it, the game will freeze with no will to suspend the software, forcing the player to turn the system off.
The player can fix this by going to the Nintendo eShop and doing a Repair Software to function normally afterwards or the player can avoid the Sniffle Thwomps to prevent freezing.
Bowser's Memory ML Crash
While fighting Bowser's Memory ML, it's possible to use a Bros attack like the Green Shell to kill Memory L while Memory M is knocked out. This causes the normal death animation to play for the former, and then a game crash instantly afterwards. Presumably this is because the animation that's meant to play when both memories are defeated requires both to be on screen, and the death animation won't be able to play if one of them isn't present.
Bowser Jr.'s Journey glitches
Glitches that only appear in the Bowser Jr.'s Journey mode of the game.
Big Tail Goomba Dummy Boxes
Enemy Failed Counterattack Glitch
In one mission, when a Para-Biddybud tries to counterattack the players minions, sometimes they will dodge the minions attack, but never actually counterattack. This forces the player to have to quit the mission to reset.
Random Game Crash
The game may crash randomly in the formation menu.
As of patches, these glitches are impossible to perform.
Luigi Freak Out in Dimble Wood (Patched in Version 1.1)
If the player goes back through Dimble Wood once Mario is separated from Luigi, they eventually reach the room with the Wiggler. In this room, once Luigi touches the wall near the Wiggler, he starts freaking out and warping back and forth without any input from the player. This glitch has since been patched.
Luigi Stuck in Dimble Wood (Patched in Version 1.1)
In the same room, if the player climbs the ledge to the left, Luigi's behavior becomes more and more erratic. If they then leave the area via the loading zone there, they then get stuck in an infinite loop as Luigi warps between screens non stop. Saving here "bricks" the save file, forcing the player to delete the save file and start a brand new one to continue. This glitch has since been patched.
No DS Music (version 1.1 only)
This glitch was added into Version 1.1. When the player goes to Music on the pause screen, and tries to listen to music from the original game, nothing will play. Music from the remake also won't work until the player exits and returns to the Music menu. This glitch was patched in version 1.2.