For channels that have 10 or more subchannels, no guide data is shown for the last 3 Subchannels. For example, if there are 12 subchannels like on KAGW 26, 10 through 12 have no guide data. If only 10 Subchannels like on KCTU, then no guide data on 8-10.
However, the HDHomerun app has guide data for these subchannels.