Continuation Contracts using Eikon .NET API

I am trying to pull continuation contract (XXXc1, XXXc2, XXXc3) settlement data via the Eikon .NET API and there are a few instruments it doesn’t work for e.g. JKM and SEP.

When I use the Eikon Excel addin I can pull the data fine, but not when I implement in C#. I know my code works because it works for other instruments like NCFM, YBV, NEA, SEF.

Even more unusual is I can pull JKMc1 and JKMc2 but not JKMc3 onwards.

Is there anything to check which might explain why I can’t access the data?