Google withholds high ranking ability on new sites, by de-valuing
the new links for 2-4 months. If the domain and backlinks have existed
for a certain length of time (4 months?), then you are OK, and escape
from the sandbox.
This penalty is new-site based.
Long-standing sites have no trouble ranking new pages. Over time, the
newly generated links are given weight, and eventually the sandbox
effect goes away.