Replace the pump. Sounds odd, but a worn pump will sometimes let water slide back past the impeller. Then do a couple of tub clean cycles. Any time there's leftover water that you can see in the tub, the filter should be cleaned first, then change the pump if that doesn't do it.
I've worked on a LOT of LG frontloaders, but not toploaders. Do they even have a filter? The pump info is good, however.
Have a good'un