Replication consistency is broken as workers miss the error notification from an earlier failed group.

Enable parallel replication on slave.
slave_parallel_mode='optimistic'.

Table Structure:
CREATE TABLE t2 (a int PRIMARY KEY) ENGINE=InnoDB;

Execute following DML operations on master.

INSERT INTO t2 VALUES (32);
INSERT INTO t2 VALUES (33);
INSERT INTO t2 VALUES (34);

The above three transactions are scheduled for parallel execution on slave.
The first insert fails on slave due to duplicate key error. Upon error the rest
of the workers should abort but transaction 34 gets committed.