that's because there is no setting for OTA EPG.This was using the LATEST version of the Nebula software downloaded from the start of this discussion, within the settings menu (quite extensive) nothing about OTA EPG grabbing only a EPG update button, and with the 2 minute cutout limit on TV, do not know if this time limit affected the EPG.the nebula software does NOT take the EPG from anywhere other than "over the air".
it just does it on it's own. those EPG settings you are seeing should really be removed as the 'download from web' settings hasn't been usable for years.
you would probably need at least a good few minutes for the EPG to full populate. so the 2 minute limit probably isn't enough time for it to do it.