We are using Spartan-6 MCB in our design. The timing analysis does not analyze from a flip-flop to the MCB "sysrst" pin in a period specification.
Is this a known issue?
This is a known issue and is currently under investigation. This is scheduled to be fixed in the future release of software.
The workaround is to place the sysrst driver (flip-flop) near the MCB, to insure the routing is very small.