A federal appeals court said the U.S. government was right to challenge Illumina’s purchase of cancer-test developer Grail, but still sent the case back to the Federal Trade Commission for reconsideration.

A three-judge panel found the deal to be anticompetitive, but said the FTC erred in how it considered Illumina’s proposed fix for its drawbacks. The judges ordered the FTC to reconsider its opinion on the troubled deal, which the European Commission has already ordered Illumina to unwind.