The F136 alternate engine was running on the test stand, and sustained minor damage, which led people to rumors that the combustor needed to be redesigned.

It now turns out that the problem is much less severe than originally reported. The damage was from a lug that attaches the diffuser to the combustor that came loose during testing.

Obviously, this is not something that you want happening on an aircraft in flight, though the damage was minor, and not noticed until the engine was torn down after a test run, but it’s a not uncommon thing to have happen at this state of the development process.