[Dumyat]

 I would definitely raise this as a github issue. If it changes over time my guess is it will be tricky to find the cause but no one might be aware of it. You will need a debug log and screenshots (which you have). Just be clear about the fact it's your own skin and that as it's not displayed in the default skin because that field is not used.

Before you raise the issue can you check the duration of the programme before and after the one with the error. It's possible it's picking up the wrong EPG entry and using that instead which could mean it's a bug in the addon and not Kodi proper.   

I'll definitely raise it as an issue with before/after screen shots and debug logs. Will keep my eyes peeled for another example of this happening. Maybe an idea for me to temporarily add duration to the guide screen on the stock Estuary skin with my own set-up and see if the same behaviour occurs. Then I can demonstrate the issue is not unique to my own skin mod.....