Verified all references to `importStatus` are either:
- SQL patches creating the column;
- reads;
- writes immediately before an insert; or
- explicit updates of the column.
That is, I identified no cases of `setImportStatus(X)->save()` on a Commit which may already exist. This //would// break that.
In general, almost all writes go through `$commit->writeImportStatusFlag()`, which is an explicit update.