My personal understanding is that whenever one add data in the GUI or with XOG (including XOG in gel) the system uses java and writes directly to the blobs. Further my understanding is that the blobs do not have any limitation to the time frame for which they can store data. They store the periods and the value and any number of the combinations.
I should think that is something else.
Try to get out the actual XOG from the data feed when it fails and compare it to the successful manual XOG.