instaciating the same architecture twice gives different results

ok, let me try...

I test my transmitters by activating only one subcarrier so I expect to see a single sinusodial wave on the DAC outputs, but one of the outputs (it's not always the same) oscillates in a more less random looking way.

The setup and hold times at the DAC are not violated because I use a seperate clock for every channel of the DAC (delays are different on the board), and I can adjust the clock phase during runtime so that the data are sampled correctly.

It appears to be that there is some sort of metastability problem?

There are several different clock domains in the design, but I think I handle the transistions from one clock domain to another correctly (use synchronizers, reset sequencer), and TimeQuest doesn't report any errors which it should if there is a timing violation (if my timing constraints are correct)

thanks for your help, because I'm really desperate.

Christoph