Problem with pump while winterizing 2021 T@B 320S

So, while going through the winterization process, via the checklist (Thanks, Sharon Is Sam!) everything was going smoothly until I got to the point of trying to fill the plumbing with Antifreeze.

The AF bottle was set up with the hose connected to the "Winterize" inlet, Alde bypass switch in vertical position, blowout valve removed and "City Water" inlet capped, and all drains/faucets closed. Pump is then turned on. Waited for a couple minutes, but pump does not stop. It continues to run, and never stops.

So, naturally, when faucets are opened, no AF flows through. Pump continues to run, but apparently no pressurization occurs. Now, in all honesty, I have never used the water pump for anything before. We have always camped at sites with electric & city water hookups, and so have never filled the fresh water tank or ran the pump.

Last year, the dealer was having a special on winterization, so we had it done there. I'm presuming that the pump was working then, so I'm not sure what is going on here now.

Anyway, since overnight freezing temps are here now, I went ahead with blowing out all the lines with the compressor, and so completed the non-AF winterization method. However, I'm still trying to figure out what to do about this, and any help would be most appreciated. Thanks in advance.

(Title edited for search purposes.  Moderator)