Page 15 of the Quartus® II software version 8.1 Release Notes contains an entry for the problem "When two PLLs that both use dynamic reconfiguration are cascaded, dynamic configuration may not work correctly." This problem statement is not exactly correct.
The problem can occur when the upstream PLL uses reconfiguration even if the downstream PLL does not use the reconfiguratoin feature. In addition, the symptoms of the problem may be a compilation that does not fit, or a software internal error.
A patch is available to fix this problem, and the problem will be fixed in a future version of the Quartus II software. Refer to the Related Solution below for details.