New bug or old bug, M&M have a bug, I believe they are supposed to give their own or each others Summon item when you answer all questions correct. They only give Moxxie's for some reason.
M&M quiz machines are also bugged, they are supposed to let you buy their Summon items for about hundred souls. Sadly the range or area for interacting with the machines isn't correct so I have to no clip into the machine to interact with it to buy the items.
Verosica Mayday's room has a bug that makes the doors leading to the bedroom not let you pass through, they just glitch or move as though you are passing through. This makes it impossible to go to that part of the area or map.
Currently, Joiplay makes it manageable, just turn on no clip and move there and just cheat the Summon items into inventory.
I have also encountered a bug that causes the RoboMaid to vanish or become unreachable after she has been activated and becomes accessible as a companion. She is supposed to be charging at night, but is instead not where she is supposed to be and I can't find her at all.
The Demon Rat/Rabbit thing you get in the lab as a companion, also seems to have a bug, they are not interactable after you get them a bed and let them rest. I do not know for certain, I just assume that since I can't interact with them and don't know how long they need to rest that they are bugged.
I used Joiplay and added a single point to the characters affinity when this happened. So 3 to 4, which I guess are stages in affinity. This allowed me to give the Demon Rat/Rabbit thing a carrot or whatever it eats and continue the character's development as a companion.
The Side Missions for hunting enemies at certain times outside in the Car Parking area have bugs as well. Moxxie and Millie are bugged in two ways, as they are supposed to join you for the job since they are the ones putting it up, they do not join you to hunt the targets as they seem to be stuck with the dialogue for the quiz machines, and they for some reason reset the Quiz Game count to zero. So unless you use a Summon item they will not fight beside you. The Quiz Game count, is a counter for your progress in the Quizzes you take with M&M, the more Quizzes you complete the higher this counter goes which improves your rewards and increases the variety of questions. So this bug setting it back to zero, really robs a player of their progress and potential rewards, alongside a very good learning experience about guns and the body.
It is explained in game that the Relationship Checker thing the player can access is not complete but I just felt like saying it here that the Buddy Manager or key item the player gets is not accurate. When the device is used to see Loona's Relationship with the player it is either very wrong or a few stages behind. So currently memorization of events is needed to keep track of how well things are going.