It is possible for the data on the master and slave to become
different if a statement is written in such a way that the data
modification is nondeterministic; that is, left up the query
optimizer. (In general, this is not a good practice, even
outside of replication.) Examples of nondeterministic statements
UPDATE statements that use
LIMIT with no
clause; see Section 126.96.36.199, “Replication and LIMIT”, for a
detailed discussion of these.
Also see Section B.5.8, “Known Issues in MySQL”.