This is actually getting kind of tiring, every change you guys make comes with a billion+1 OBVIOUS bugs. There's nothing subtle here, these are clear functionality bugs, which makes it painfully obvious that once you code something in you don't take the time to test it.
Honestly, I don't know what kind of development model this is, where I work, for every patch there are 200 something automated functionality tests and manual testing as well, before we deploy it. So, in conclusion, just develop some damn tests and let them run to make sure the minimum functionality is there before you deploy an update.