The two incidents of rejoice here come from two different but related Greek verbs. Paul obviously uses these synonyms for stylistic reasons, with no perceptible difference in meaning.

Wrong is too weak an English word here. Good News Bible‘s “evil” renders the meaning of the Greek.

Right is more likely “truth,” as in Good News Bible. The Greek word implies speaking the truth, as in 5.8: “of sincerity and truth.”

An alternative translation model for this verse is:
• People who have Christian love should not rejoice over evil, but they should rejoice over the truth.

Quoted with permission from Ellingworth, Paul and Hatton, Howard A. A Handbook on Paul’s First Letter to the Corinthians, 2nd edition. (UBS Handbook Series). New York: UBS, 1985/1994. For this and other handbooks for translators see here .