"in system memory content" editor and clock domains, really safe ?

Hi, are "in system memory content" constant really safe (I mean correctly designed) ?

I don't need to put registers after them, do I ?

A design rule checker says that all my "in system memory content" constants are not synchrnonized betwen clock domains.

Regards

Quartus 9.1 sp1 WEB edition. Win XP SP2

EDIT :

I see inclock and outclock on ports of those ISMCE in rtl viewer. So I think that different clocks are handled inside.