So my cars been very bouncy recently, even on silky smooth roads (rare here in the UK, I know!) I know there’s something suspension-related going on on the passenger side, because I can hear a knocking. I looked under the rear of the car today to check the rear springs. I notice some dampness on the spare tyre well drain plugs. Removed them and a lot of water gushed out of both. I let it drain fully. The car has stopped bouncing now! Still having the suspension issue on the front passenger side though. Car pulls more effortlessly and smoothly, handles better, feels more agile. Is it all in my head? Surely not.
Check that your 12V battery isn't also doing the back stroke. Also check the connector for the pack fan for corrosion. There is a thread discussing common causes of water leaks in the 2nd generation Prius. (Spoiler: it is often the seam on the roof under the rubber strip.) Prius trunk LEAKS pictures compilation - common problem areas. prius 2004-2015 | PriusChat
