Opening a report in preview doesn't print it. acNormal sends it to the printer. That will likely send the print job before any filtering could be applied. What might be more pertinent is that the latter syntax is the correct way. That the other syntax worked in preview was happenstance, I'd say. IMO the main objective with this process would normally be to open the report filtered, then send it to the printer but via code steps, not acNormal. If you don't want to see the report you open it hidden.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.