If one channel is 5 hours out and the rest are correct, your provider needs to fix it. If all channels are 5 hours out then you can fix it - most apps have an EPG offset (which is the number of hours to adjust by).

Have you tested to fix your offset to epg? I mean if it´s 5hrs late then just put your timezone -5hrs?

And of course, provider should add there timezone in files. Or just simplified fetching directly from source so then channels epg are always on time but then you need to add timezone each country ur self. Sorry my bad english.