Something odd there. Which DVR model?
Should be press DVR button scrool to manage series recordings, press right, scroll to show, press ok, (options including change priority, modify series and cancel series. Modify Series. press ok. Options on that include episodes (first run only/first run and repeats). Scroll to episodes, press enter, change as desired, press ok, push right to save, press ok. close menus, may have to do repeated exits.
You may also want to find the dvr settings to set your default options for creating series recordings. menu/settings/system/dvr/default series options