The only thing I can think of, and this is a way out there sort of guess, is that something might have somehow gotten hot or soft under the hood, and one hose has fused with another hose, with a pinhole leak somehow linking the two hoses.
I know the rubber in two tank in mine over the years has swelled, in reaction to chemical action ( likely after I moved dev into two where it had sat in blix for years - tank 1 thermostat issue drove that swap), and I had to take the bottom off to shorten the hose from pump to heater. The swelling caused the short pipe section to kink as it grew longer.
The thing is not mind blowing to diagnose once you remove the top and racks, flip it over, mop up the residual fluids, and take about 6 screws out from underneath.
Yes a dishwasher is an apt analogy. There is a power cord to the vent fan to disconnect, and then reconnect so the wire does not rub against the fan. Ask me how I learned that detail after I had refilled the machine.
The thing to remember on the electrical side is that at it's heart it is a japanese 100Vac machine, that runs it's pumps and processor control circuits from an auto-transformer (maybe a full tx, I am a little fuzzy on that precise detail) to take NA 120Vac in and step it down to 100Vac. Only the heaters run at 120V.
Happy troubleshooting. It will make you stronger in the long run with this machine.
The next thing to likely crap out are the control board electrolytic capacitors. Not a huge effort to swap, but necessary on many older pieces of gear.