Dri Driving fine doesn't mean your HV system is OK. You got pull off the pack cover to assess if there are water poddles in there.
The corrosion you see is fairly typical for the negative terminals. It's hard for me to tell, but if those are heat marks (not just oxidation) on the bus-bars, that would definitely need investigation. Your freeze frame info shows a 526 and 614 code. The info below was from an earlier post on a different thread, by @Patrick Wong Personally, if you drove through flood water, yet the battery pack is dry, I would focus on the engine compartment items. DTC P0AA6 means that the high voltage system has a ground fault. Normally that system is totally isolated from the car body. If a ground fault occurs, this DTC is logged. The bad news is that info code 526 means that the ground fault could be anywhere in the high voltage system, including the traction battery, the battery ECU, the cable that connects the battery to the inverter, the inverter, the transaxle, or the air conditioner compressor. BTW, there are a couple of TSBs relating to P0AA6. If info code 613 also had been logged, then T-SB-0306-08 suggests replacing the transaxle. If info code 614 was logged, TSB EG017-05 suggests replacing the inverter.
And then read this for additional good info to help understand what you're seeing (not your EXACT situation, but good info): Art's Automotive
WOW! He is the first one I've heard that says water is NOT a conductive of water! Smart man! It's actually the impurities IN the water! That was a good and informative article. Thanks for posting the link!
There is another Techstream measurement that shows a reading of 0-5v that is an indicator of how well the HV system is isolated from the car body. 5v is the perfect isolation and 0v is direct short. I don't remember the exact nomenclature for it right now, but I'll bring it up on my techstream when I get home and post it here. It's something....Wave or Wave..something
Your photo in post 19, at the bottom of the screen clearly shows Detail Code 2............526 Detail Code 3............614
And now I see the ShortWave reading in your picture on post 35 is showing a 0.03v. You have almost a dead short somewhere. Try unplugging the AC compressor. If you see the shortwave reading going higher then you're finding the problem. I would focus on making sure I don't have water in any of HV connections where the battery cables connect to the inverter, inverter connects to AC, transaxle, etc. Something has water in it........