2010 Camry Hybrid Trunk Water Issues

[runnman]

Need some help with this. I found water in the trunk of my 2010 TCH; only on the left side as I know.
The 12 volt battery covers the right side and difficult to tell if there is water there.
No water in the spare wheel area or on any matting. Water is in the left side fender well area.
Took the TCH to the dealer. The dealer had it for most of the day and reported that they had put a technician in the trunk and another putting water on the vehicle
and could not find any water coming into the vehicle and into the trunk area. They reported the Moon Roof drains were in proper order without any leaks.
They reported that the technicians found that the Rubber Plugs at the left side and other places were not installed and there was an open hole where the Plugs would fit.
They installed Rubber Plugs in places where they were absent. One, I can feel and is located on the left side where the water is found.
And they thought by driving in the rain, this may be how the water entered the trunk area.

After the next hard rain, I found water again in the same area (the area was completely dry after the Rubber Plug fix.) The installation of rubber plugs is not the fix.
I have an appointment to return the TCH for additional work on this trunk water issue.

Here is another thought which comes to mind.
The Hybrid Traction Battery requires ventilation for proper operation. There is the fan assembly on the rear shelf which pumps air into the trunk.
How does this air exhaust or circulate? Maybe those Rubber Plugs should not have been installed? Should the holes have been left open for circulation?

So, my two issues:
1. Anyone have any thoughts as to how the water gets into left side of the trunk?
2. And, should Rubber Plugs be installed or should the holes be left open for circulation?

I do not have enough knowledge when issues like these arise and any help will be appreciated.