@Da Johnson, just before you send to the printer there should be a setting to choose single or double sided printing. The setting will Stick from the last time someone printed. You should be able to choose single sided. If you do see the setting is already set for single sided then it sounds like your printer is overriding that setting.
You might also want to post your issue to the FamilySearch Center Category at https://community.familysearch.org/en/categories/family-history-centers