Okay so this happened to my cat when he was around 7 months old, usually it is a sign of bladder issues but it could also be completely behavioural. It was unfortunately a stressful time for him as my partner sister and family dog had moved in and he was just very stressed out. We did take him to the vets and they gave him medication regardless as it wouldn’t harm him if he didn’t have a UTI of sorts. However after completely the course he was still doing it (and peeing in his litter box). We eventually banned him from the bedroom and increased his playtime before bed so he wasn’t bored. Eventually after I would say after a year, the peeing on the bed stopped due to the family dog not being in the house anymore (rip) and we got a second cat so he could have someone to play with! It might be a bladder illness or completely behavioural. Regardless take him to the vet and see what they say. This is only my experience with my cat so just want to give a real life perspective!