Frontloader Doesn't Drain Properly

I have a LG front load washer (#WM2016CW). I notice that after each wash cycle, a small puddle of water remains inside the tub. The clothes that sit on top are in perfect condition--they are almost dry, but the clothes that sit at the bottom are wet due to the water that has remained in the tub. My machine spins perfectly, makes no weird noises, and drains with full power. I replaced the drain pump thinking that it had gone bad, thus contributing to the water remaining after each cycle. But this didn't do any good--the water still remains. It is important to note that when I do a "rinse/spin" cycle with no clothes in the tub or a "tub clean" cycle, no water remains inside the tub after the cycles are complete. On occasions, when my load of clothes is small enough, no water remains in the tub either.

Since the clothes that sit on top are almost completely dry, I wonder if the machine completely drains when it should, but then something allows water to get back into the tub thus wetting the bottom clothes. Is that possible?

Also, since water drains full force, I cannot imagine there are any hoses/pipes clogged. I've checked and found nothing. Also, no error number has ever appeared on the screen panel. What can be the wrong with the machine? I appreciate any help I can get!

Feeling frustrated...