The upgrade from 1.12.3 to 1.12.4 breaks the storeByForeignSource feature. There are two side effects after the upgrade:
The RRD data is stored in
If you know this behavior, you can move your data before the upgrade just one directory higher.
The bigger issue which results in a loss in your RRD data collection is, the data isn't stored as foreignSource anymore, it is stored as the nodeId.