Why do new patches always seem to break the game?

I could be wrong, but isn't the PBE used to test new patches and other things? If so, if PBE also full of bugs? I'm not understanding why none of the bugs or issues are tested before new patches go live. I wouldn't mind less patches if it would actually allow time to properly test them.

I've also noticed that the Autofill Protection feature isn't work. Is that all because they changed Ranked? Are these bugs expected to be present start of season as well? With months of planning for the new Ranked, doesn't seem like it is going very smoothly. January will be here sooner than Riot knows it.

Good luck on the ri/ft.