[sv-ac] Question about sampling of automatic variables

Hi,
 
In section 18.16, in the description of expect statement, the LRM says
that properties can refer to automatic variables of the tasks in which
they are defined. My question is how the sampling works on these
automatic varibales ? Or there is no sampling of these variables and
properties just use the same value which was at the time property
started evaluating ? Or something else ?
 
Thanks.
Manisha