Memory systems, memory controllers, and operation methods of the memory systems are disclosed. In one example aspect, the memory system may suspend a target operation, such as a program operation or an erase operation, based on whether or not to execute a first operation of resetting a reference read bias when a failure occurs in a read operation executed after the target operation is suspended, and a number of times the target operation is suspended. In this way, the memory system may reduce a delay associated with the suspension of program operations and erasure operations.