As strange as it might seems:
delete from SPRStrata.SBMSData.sro.MediaPlanAdMap_Staging - error
delete from SPRStrata.SBMSData.sro.MediaPlanAdMap_Staging where mediaplanid = mediaplanid - works, although logically similar to previous one (assuming there are no NULLs)
delete from SPRSTRATA.sbmsdata.sro.MediaPlanAdMap_Staging - works
insert into SprStrata.SBMSData.sro.MediaPlanAdMap_Staging ( MediaPlanId, AdId )
values ( 1, 1 ) - fails - 'The statement has been terminated.
Msg 16933, Level 16, State 1, Line 1
The cursor does not include the table being modified or the table is not updatable through the cursor.
insert into SprStrata.sbmsdata.sro.MediaPlanAdMap_Staging ( MediaPlanId, AdId )
values ( 1, 1 ) - works
It looks like that making database lowercase(d) make query works in all scenarious. That doesn't make much sense to me.