I have in the past come across dishwasher plumbing where the drain pipe is connected to the sink/ basin drain. If the drain backs up/ gets choked, dirty sink water will run into the washer unless the the drain pipe is routed as per the manufacturer’s handbook.
Check sink drain if the washer is connected to it. You could uncouple the dishwasher drain pipe and run the dishwasher (with drain in the sink to permit drainage). Ensure the disconnection is made good or the water may run out of the disconnection.
If the machine works OK and the level is OK, and no more soapy water then suspect the drain.