WHIRLPOOL wdta50sahz0 draining while filling

I've run out of guesses what issue is so hoping internet brain might know. Originally thought issue of arms not spraying water was circulation pump so replaced whole bottom assembly that came with pump. Still same issue. Took door apart to be able to fool latch to see what happens during cycle. The tub fills with water but it gets drained at same time. Pretty much just sending water to the disposal. Drain pump goes off when water gone. If i unplug the drain pump, water fills and arms spin doing what should. I thought maybe control board next cause, but that made no difference replacing. Drain pump functions problem is doing it at wrong time. If I guess wrong in next part I might as well have gotten new dishwasher by then. Washer completes all cycles no problem, just gets no water staying in there to clean with. Time to blame the drain pump or something else?