I know it's so weird looking at old records.I did that with KiKi and couldn't remember some of the things that KiKi had.I'll bet it surprised you about Tubby peeing on the bed.So long ago.
Tucker peed a few times on our bed.(when he was about 2 months old or so).He had UTI.So many kittens have that in the beginning of there life.It seems anyway.
My vet said nerves can cause it as well as food.
But maybe kittens miss their mom's and are so darn nervous being alone away from them.Or just being somewhere new.