Strict UML requires a Multiplicity indicator on each end of a relationship, ie 1..*, 1, 0..* etc. Only in UML2 is it an option to omit the indicator in the case that it is unary, ie 1. IMHO this is bad practice, especially when teaching novice A&D people as I do. I always insist that they spend time thinking about the relationship and indicate specifically the value. I notice that your UML editor always omits the “1” . I would prefer if this were a user selectable preference – it may be, but I can’t find it.
Not a bug, just annoying.
John