If you stop it while it is agitating and put it in spin, it will pump and drain at the same time. What causes it to only pump and then spin when the water is all out?
Assume you meant it will drain and spin at the same time. It shouldn't do that. Stopping the washer during agitation and going directly to spin is no different than the timer doing it automatically except for one thing. Drain is in high speed only, no matter what speed may be selected. If your manually placing it in spin that is low or extra low speed, the latch may not engage and it will do a spin drain. I just tested one by running in dry agitate for 15 seconds, stopping the washer, selecting high speed spin, start washer. It went into drain only. Of course, you then must stop the washer and start again for it to go into spin.