How do I fix water not staying in the wash tub of Twin tub, LG WP 750R?

Water doesnt stay in the wash tub. It drains as water is put in the tub. The Drain/Wash knob is set to wash. Kindly assist. Thank you. The spinner works well.

If your drain is not high enough the water will siphon out while filling. Check your owner's manual for correct height, usually about 39 inches from ground