I've worked on multiple teams at completely different companies years apart that had the same weird rules around "story points" for JIRA: Fibbonacci numbers only, but also anything higher than 5 needs to be broken into subtasks. In practice, this just means, 1-5, except not 4. I have never been able to figure out why anyone thought this actually made any practical sense, or whether this apparently is either common enough to have been picked up by both teams or if I managed to somehow encounter two parallel instances of these rules developing organically.