The number of problems should decrease over time. The nature of the problems should change over time, as you test the system's different limits. Don't fret about new machines that are announced for delivery after your project is supposed to be finished. A chip in the hand is worth two in the press. Do fret about machines that are actually available and functional.
New technology is a moving target, particularly system software.
There are new ideas and tools from academia and from other industrial or government customers, and continuing developments by the manufacturer. You can help push the technology forward, and you must be prepared to use advances when they become available. Keep overhead under control. Programmers will encounter new problems, such as communication overhead in a multiprocessor. Allow them time to adjust.