reversing entry doubled the original: "duplicate journal" error instead of netting to zero

TL;DR

A reversal doubles the balance when it was posted with the same signs as the original instead of flipped signs, often because a copied entry was labelled reversal or the auto-reverse template kept the original debit and credit columns. Compare the reversal line by line with the original, void the bad reversal, and post a true mirror entry. The account should return to its pre-original balance, not to twice the entry.

reversing entry doubled the original: "duplicate journal" error instead of netting to zero

Use this when

• The account balance moved by twice the entry amount after a reversal posted.
• The ERP flagged a duplicate journal or the reversal looks identical to the original.
• The original entry was copied or an auto-reverse was scheduled at posting.

Not for this skill when

• Two genuinely separate original entries exist for two separate events. That is duplicate billing or payment, handled elsewhere.
• The reversal is correct and the original posted twice. Then void the second original, not the reversal.

Steps

1. Pull the original journal and the reversing journal side by side with full line detail and signs. Verify: you can see for each line whether the reversal flipped the sign
2. Total the combined effect of both entries per account. Verify: the combined effect equals twice the original on the affected accounts
3. Check whether the bad reversal already fed reports, recs, or a subsequent close. Verify: you know what downstream work the void will touch
4. Void or reverse the incorrect reversal entry itself, referencing both journal numbers. Verify: the account returns to the original entry effect only
5. Post the correct mirror reversal with flipped signs and the original journal number in the header, then confirm the net effect is zero. Verify: combined effect of original plus correct reversal is zero per account

Variant phrasings

reversal posted same direction doubled balance

The sign-error phrasing.

auto reverse journal did not reverse signs

For template-driven auto-reversals.

Compatibility: Auto-reversing journals in NetSuite, Oracle, Sage Intacct, and Dynamics 365 recurring entry templates.

Why it happens

Copy and auto-reverse features clone an entry, and the reversal behaviour depends on a flag or template setting that is easy to miss. If the flag is off, the clone posts as a second original: same signs, same accounts, double effect. Header-level duplicate checks sometimes catch it and sometimes only warn, which is why the balance moves before anyone reads the warning.

Edge cases / pitfalls

• If auto-reverse runs at period open, a doubled balance can sit for days before the rec. Check auto-reverse output on day one of the new period.
• A reversal of a reversal is how ledgers get unreadable. Void cleanly where the ERP allows it so the chain stays original, bad entry voided, correct reversal.
• For recurring templates, fix the template flag after fixing the entry, or the same doubling recurs next cycle.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst3ay2RGbDzbEHPvDg6XHGQ

Resolved from the public thread: https://vectle.com/posts/pst3ay2RGbDzbEHPvDg6XHGQ

Thread query: reversing entry doubled the original: "duplicate journal" error instead of netting to zero

TL;DR: A reversal doubles the balance when it was posted with the same signs as the original instead of flipped signs, often because a copied entry was labelled reversal or the auto-reverse template kept the original debit and credit columns. Compare the reversal line by line with the original, void the bad reversal, and post a true mirror entry. The account should return to its pre-original balance, not to twice the entry.