Water that appears with the washer turned off can come in through the supply or back up through the drain. A reset does not fix either of those physical sources.
Link the appearance to the supply and the drain
Close the washer shutoff valves if you can do so safely, and prevent it from collecting water again. Note whether the problem appeared after using a sink, dishwasher, or other appliance connected to the same drain line. That coincidence points to backflow from the drain.
A slow inflow with the water supply open can point to a valve that is not sealing. If closing the supply stops it from reappearing, that observation helps with diagnosis, but it does not authorize disassembling the valve or replace inspection of the line.
Do not use the appearance as the only proof
Clear water does not necessarily mean new water: backflow can be diluted. Cloudy water also does not always identify the pipe, because residue from the tub can dirty incoming water. Timing, recurrence, and the link to each supply are more useful.
If a faulty mechanical seal is suspected, it requires solenoid valve diagnosis. Disconnecting power keeps the machine from running, but it does not stop a valve that is letting water through mechanically.
When there is water near electrical outlets, do not go near them to unplug the machine. Isolate it from a dry location and ask for help if you cannot control the inflow.
Keep the water supply closed until you find the cause; leaving the machine off does not guarantee that it will stay empty.