In reply to Srini @ CVCblr.com:
I think I may have gotten close. I have come up with the property…
property prop_sig_stable(rst, sig);
@(sig)
$changed(sig) |-> $changed(rst);
endproperty : prop_sig_stable
this property appears to work in detecting the situation that I desire; however, it seems to flag the assertion on the edge of sig following the actual error.