It may be due to the aforementioned occurrences or it may be caused by a slightly below ideal strike pressure or slightly below ideal planchet thickness (mass). Either way, it's within the realm of normal operations when striking coins.
In Memory of Crazyb0 12-26-1951 to 7-27-2020
In Memory of Tootallious 3-31-1964 to 4-15-2020
In Memory of T-BOP 10-12-1949 to 1-19-2024