In 9 out of 10 cases---this is due to a weak/failing (intermittently slow) DRAIN MOTOR.

Since the MODEL & SERIAL number are not provided---it's hard to know for sure. Most often this occurs in LG washers at or about 5 years old and used often (a family of 4 for example).

The function of the black anti-siphon hose (pictured) is to prevent *continuous draining* of water---especially right after a drain cycle has completed---and rinse-water begins entering the tub.

Particularly in circumstances---where an installer has jammed the drain hose far into a drain standpipe (into the "trap") or secured the hose to a utilitub---with the outlet at the bottom of the utilitub.

Early LG washers were prone to complaints of : "Fills & Tumbles/Loses Water--- Fills Again & Tumbles/Loses Water---repeatedly.

The black anti-siphon hose was added to remedy this symptom.

Part link to the drain pump for an LG washer with a 365-day return policy ==> http://www.repairclinic.com/PartDetail/Drain-Pump/4681EA1007G/1468049

And how to replace it...