ios - Fetched Property not working -

i have core data setup 2 configurations aka 2 store files (one holds entities predefined stuff(the nobackup store), other 1 user generated content (the backupstore).

in example 1 entity in backup store has fetchedproperty nobackup store. nsentitidescription of entity in question this.

$2 = 0x07b7a790 () name pilotmedical, managedobjectclassname pilotmedical, renamingidentifier pilotmedical, isabstract 0, superentity name (null), properties { classcreationdate = "(), name classcreationdate, isoptional 0, istransient 0, entity pilotmedical, renamingidentifier classcreationdate, validation predicates (\n), warnings (\n), versionhashmodifier (null)\n userinfo {\n}, attributetype 900 , attributevalueclassname nsdate, defaultvalue (null)"; classexpirationdate = "(), name classexpirationdate, isoptional 0, istransient 0, entity pilotmedical, renamingidentifier classexpirationdate, validation predicates (\n), warnings (\n), versionhashmodifier (null)\n userinfo {\n}, attributetype 900 , attributevalueclassname nsdate, defaultvalue (null)"; country = "(), name country, isoptional 1, istransient 1, entity pilotmedical, renamingidentifier country, validation predicates (\n), warnings (\n), versionhashmodifier (null)\n userinfo {\n}, fetchrequest (entity: country; predicate: (country_id == $fetch_source.country_id); sortdescriptors: ((null)); type: nsmanagedobjectresulttype; )"; "country_id" = "(), name country_id, isoptional 1, istransient 0, entity pilotmedical, renamingidentifier country_id, validation predicates (\n), warnings (\n), versionhashmodifier (null)\n userinfo {\n}, attributetype 100 , attributevalueclassname nsnumber, defaultvalue 0"; initialexamdate = "(), name initialexamdate, isoptional 0, istransient 0, entity pilotmedical, renamingidentifier initialexamdate, validation predicates (\n), warnings (\n), versionhashmodifier (null)\n userinfo {\n}, attributetype 900 , attributevalueclassname nsdate, defaultvalue (null)"; lastaudioexamdate = "(), name lastaudioexamdate, isoptional 1, istransient 0, entity pilotmedical, renamingidentifier lastaudioexamdate, validation predicates (\n), warnings (\n), versionhashmodifier (null)\n userinfo {\n}, attributetype 900 , attributevalueclassname nsdate, defaultvalue (null)"; lastekgdate = "(), name lastekgdate, isoptional 1, istransient 0, entity pilotmedical, renamingidentifier lastekgdate, validation predicates (\n), warnings (\n), versionhashmodifier (null)\n userinfo {\n}, attributetype 900 , attributevalueclassname nsdate, defaultvalue (null)"; lastocularexamdate = "(), name lastocularexamdate, isoptional 1, istransient 0, entity pilotmedical, renamingidentifier lastocularexamdate, validation predicates (\n), warnings (\n), versionhashmodifier (null)\n userinfo {\n}, attributetype 900 , attributevalueclassname nsdate, defaultvalue (null)"; lastrenewaldate = "(), name lastrenewaldate, isoptional 1, istransient 0, entity pilotmedical, renamingidentifier lastrenewaldate, validation predicates (\n), warnings (\n), versionhashmodifier (null)\n userinfo {\n}, attributetype 900 , attributevalueclassname nsdate, defaultvalue (null)"; medicalclass = "(), name medicalclass, isoptional 0, istransient 0, entity pilotmedical, renamingidentifier medicalclass, validation predicates (\n), warnings (\n), versionhashmodifier (null)\n userinfo {\n}, attributetype 700 , attributevalueclassname nsstring, defaultvalue undefined"; nextaudioexamdate = "(), name nextaudioexamdate, isoptional 1, istransient 0, entity pilotmedical, renamingidentifier nextaudioexamdate, validation predicates (\n), warnings (\n), versionhashmodifier (null)\n userinfo {\n}, attributetype 900 , attributevalueclassname nsdate, defaultvalue (null)"; nextekgdate = "(), name nextekgdate, isoptional 1, istransient 0, entity pilotmedical, renamingidentifier nextekgdate, validation predicates (\n), warnings (\n), versionhashmodifier (null)\n userinfo {\n}, attributetype 900 , attributevalueclassname nsdate, defaultvalue (null)"; nextocularexamdate = "(), name nextocularexamdate, isoptional 1, istransient 0, entity pilotmedical, renamingidentifier nextocularexamdate, validation predicates (\n), warnings (\n), versionhashmodifier (null)\n userinfo {\n}, attributetype 900 , attributevalueclassname nsdate, defaultvalue (null)"; nextrenewaldate = "(), name nextrenewaldate, isoptional 1, istransient 0, entity pilotmedical, renamingidentifier nextrenewaldate, validation predicates (\n), warnings (\n), versionhashmodifier (null)\n userinfo {\n}, attributetype 900 , attributevalueclassname nsdate, defaultvalue (null)"; pilot = "(), name pilot, isoptional 0, istransient 0, entity pilotmedical, renamingidentifier pilot, validation predicates (\n), warnings (\n), versionhashmodifier (null)\n userinfo {\n}, destination entity pilot, inverserelationship pilotmedical, mincount 1, maxcount 1, isordered 0, deleterule 1"; }, subentities (null), userinfo { }, versionhashmodifier (null)

but access country value exception raised. trace here. seems have undefined key country entity has country_id property. don`t know else can do.

i've fetched country object normal fetch request given country_id , works. i've switched on sql debug there no statement generated fails before.

what else can do?