After updating to SendSuite Xpress version 3.30 or Ascent version 10.30, First Class Package shipping labels for carrier POS with service 1C have the incorrect description "USPS Priority Mail" instead of the correct description "USPS First-Class PKG SVC-RTL".
There was an incorrect setting in the update.
Download version 3.30/10.30 Patch 1
and apply it to the SendSuite Xpress or Ascent system.
UPDATED: January 08, 2021