I have worked in the electronics industry and from experience there are occasions where products do get released while there are still known bugs. Microsoft has admitted to major releases of Windows with over 1,500 known unresolved bugs many of them major. It is mathematically impossible to test every possible circumstance or combination. Apples Public beta programs is an effort to expand the number of tested combinations.
Where new hardware such as the new iPhone is involved, it is possible to test the hardware functionality against published standards and design goals 100%. But when the hardware is mated with new software and subjected to the real world variety of cell towers, transmitters, receivers, signal propagation, and variations toward the outer reaches of the standards the number of possibilities for failure once again approaches infinity. Under pressure a product may get released with known or suspected issues, especially if the developers believe the bug will occur only in very rare circumstance and a software fix is known and under development. Unfortunately developers may underestimate the frequency of occurrence and/or how long it will take to develop the software fix.
Apple is particularly vulnerable to this kind of glitch because of their propensity for pushing the envelope in both software and hardware technology.
