ERPNext currently allows the same Serial No to be included multiple times in a single Stock Entry (Material Receipt) but linked to different Warehouses.
This behavior should not be possible — a single serial number should always exist in one warehouse at a time, otherwise it corrupts the Serial No Ledger and creates data inconsistency across stock tracking reports.
Example Case
In my case, Stock Entry SE-HO-MR-00034 has two rows for the same Serial No BTCENTRAL00002 —
one linked to “Mehul Patel - PEPL” and another to “Panchmahal - Amul Amcs Main”.
Here’s the affected Serial No Ledger view 
You can see both entries showing “Active” even though the same Serial No was used in two different warehouses in one transaction.
Impact
- Serial No Ledger becomes inconsistent (duplicate rows for same Serial No)
- Stock reconciliation reports become incorrect
- Traceability and audit trail breaks for serialized items
Expected Behavior
ERPNext should restrict the same Serial No from being used more than once in a single Stock Entry, even across multiple child rows pointing to different Warehouses.
