First of all welcome to the forum. intro's are nice and you will find you might get more responses that way.
ok, I had a 2013 tracer 2670bhs. No part of that slide goes into the underbelly.
Sliding the slide in or out can tip the unit one way or the other. If there water on the slide it will go inside the unit itself. If its the slide wall leaking you would see the water hopefully in the slide area inside or outside in the area around the slide not the underbelly.
You said a lot of water.. define a lot..gallon / cup...
A lot of water imo would be a leak in the pluming / fresh/ gray drains pipes or black.
Most likely fresh water or a drain is to blame. Moving the slide in / out and how your unit is sitting could make a diff on where the water sits and runs.
I would remove the underbelly or have it done to get check out.