Why is CISPro not printing labels?

When receiving a new container, checking the option "I want to print labels" does not print the associated labels for the container(s). The user has to resort to opening up the Container modal AFTER receiving to print labels. This is happening with a Zebra ZD421 printer.

After some further digging, I found that it is more likely a printer sleep mode issue. It seems like the print command doesn't wake up the printer. However, after receiving, when the user goes into the Container modal to print labels, the printer would indeed print; but will also print the first label that was sent over from the Receive page. Any thoughts on this?