So reveals a query through Westlaw’s CRIM-ALL database for off(flag & (desecrat! burn burning)) & da(aft 8/1/1992). Nor is this just in one jurisdiction — I found prosecutions in Florida, North Carolina, Pennsylvania, Texas, and Washington State. Most were dismissed, but at least two led to convictions.
I chose 1992 because since R.A.V. v. City of St. Paul it’s clear that special laws targeting flag desecration are unconstitutional even if narrowed to conduct that could be banned through more general laws, e.g., desecrating a stolen flag. Such conduct could still be punished through generally applicable laws, such as laws against theft, vandalism, and the like, but not with laws that are targeted to flag desecration.