I updated my Verizon Samsung Galaxy S5 to Android 5.0, and the only thing I have done is wipe the cache partition. Is my warranty void now?
The system constantly wiped no-longer-needed data from the cache. It's like your skin - the cells you have now aren't just older than the ones you had last year, they've been replaced by different ones. The data in the system cache is constantly being replaced by different data.
The only problem is when a new version of Android writes something to the cache that looks as if it includes some of the data the old version writes. Then Android is reading what - to it - is incorrect data. (It's like reading a sentence up to the period. If I now write a phrase with no period starting at the same place as the old sentence, then try to read it, I'll see a period so I'll read up to there. But part of it is the sentence, so the phrase makes no sense. Totally imperfect analogy, but something like that happens.)