This is a distributed system. You can have some replica that has 100, merge with an other replica and get 101. Then an other replica that also had the same 100

This is a distributed system. You can have some replica that has 100, merge with an other replica and get 101. Then an other replica that also had the same 100 merge with an other replica and get 102. Then when 101 and 102 merge, the lowest common ancestor is still 0, so you get 203.