I just took some pictures of mine to send to Jayco. It looks exactly like yours, my pictures might be a little more clear for other people to see.
The first picture shows how the side of the tub closest to the rear of the trailer is supported. There is a piece of 5/8" decking supported by some sections of 2x4. Not the greatest solution, but it seems to be effective.
This picture is the OTHER side of the tub. As you can see, the decking only goes to slightly past the drain, but doesn't cover the remaining portion of the floor. There is NOTHING supporting the thin plastic floor and helping to hold up your weight.
All Jayco had to do was extend the piece of decking past the horizontal drain pipe and put blocking over there and it would have been fine.
I sent an email to Jayco (of course it is right before the holiday weekend) asking for them to look at the pictures and determine a solution and authorize a warranty repair later this fall after the camping season in the northeast is over.
I hope they are willing to authorize the repair based upon pictures only, because that will minimize the "downtime" my trailer will have. We usually try to camp up through November, then we usually go to Florida in February. That leaves 3 months to fix it.