One of the fields in the HCSB is Old Testament Quotation. Unfortunately, some of the tagging seems to be missing. For example, of the five OT quotations in Luke 4, only one is tagged (vv 10-11). This is despite all of them appearing in bold.
It's possible the problem is a bug that occurs where the Words-of-Christ field intersects with the Old Testament Quotation field, although that doesn't seem to be a problem in Matthew 27:46 and Mark 15:34, where both fields are used together.
To demonstrate the problem, do a Bible search for Old Testament Quotations with a wildcard, in Luke 4. In the screenshot you'll see the OT verses in bold, but not getting picked up in the search.
