Washer tub fills with water after the spin cycle completes

I’m not sure about the age of the Whirlpool thin twin washer-dryer. It came with the condo and we’ve been living here for 30 months.

Initially, I thought the problem was that the water was not draining after the rinse/spin cycle completed. I have now noticed that, after the cycle completes, and the switch is off, the tub starts filling with water…

Any ideas what the problem may be??

Thanks in advance,
Vincent