Many of us have been conditioned to think that awards aren't normally subject to married sector restrictions, underlined by the (relatively) recent change to sector-by-sector pricing on BA. When married sector stuff is seen (eg on CX awards), it's notable and people ask / complain about it.

Does this mean that we've been labouring under a misapprehension all this time? Is this why searching sector by sector sometimes yields different results from searching the end-to-end trip?