I have seen a lot of threads on this already, and now the gremlin has reached me. 3.1 on two different 412's. Each unit has 2 Dig30v2, 7 Phone30, and one phone16v2. All extensions will not return a busy signal simply disconnect the PRI. The few threads I did see seemed to always roll to tier 3. Is this still the case or have we found the solution?