Processed for 26as - challan mismatch/ overbooked/ pan error

This generally happens if TRACES detects an inconsistency in the post processing validation even if the status shows up as "Processed for 26AS" initially. Not to worry this is not a huge filing mistake necessarily.

My recommendation would be:

1. Download Justification Report from TRACES; it clearly indicates the nature of the discrepancy (Challan Mismatch/ Overbooked Challan/PAN error)
2. Double check your challan particulars (BSR Code, Challan Serial number, Date of Deposit, Amount) and see that there is no overbooking of the challan in your return.

3. Check all deductions pans for any invalid or incorrect entries.

4. If any error is found, file online correction via TRACES (may need DSC for some correction).

If challan particulars are in order and there is no actual overbooking then it is possible that the issue is with TRACES validation itself; in that case register a grievance with CPC-TDS / TRACES ( after downloading Justification Report). Keep a copy of challan with you.