Currently, I am Beta Testing Version 11.5 and this is this still a problem at times. It is a known bug with AC support.

I have had some success with resetting the printer. Go to Administrator Options, log in, Set Prescription Format, 3rd block down is Select script printer, change this drop down box to your printer and the Save Prescription Preferences.

I say it is still a problem at times and I have had some success because when we set up 11.5 tech helped me fix it but then it reverted. I just went through the process to reset again today and it held and both a desktop and my laptop saved the setting and let me print a prescription without first previewing. I will see if it holds overnight.