Error/warnings in relation(s) - but why?

I’m using Servoy Offline (ie a disabled Developer) in a number of remote sites.

When updating the sites to the latest version, I am sometimes getting the

Error/warnings in relation(s)

Switch to design mode to fix the problem(s):

Relation ‘health_funds_to_schedule_lookups_list’ has no keys (is empty)

I know how to fix it in Design Mode, but I can see no reason why the error should be there. The required key fields are available to the target solution; I can recreate the relation exactly how it is in the source solution, without error.

Even more curious, there’s no pattern to which relation will generate the error. Most sites import fine, some will have an error in a single, random relation, which can be repaired without error. Usually it’s a relation which already existed in the target solution in the same form.

It’s a large solution - any suggestions on the likely cause? Because the sites are offline most of the time, it’s becoming quite a problem to rectify.

can you send us such a merged solution that has that problem?
So that we can see why it is complaining?