Raf's more recent suits manufactured by Gysemans does use fused interlining, but from what I've read, his pre-2000s suits were full floating canvas. I guess it could have been a cost/specification decision made by Raf.
Since spring 2010, Raf moved the majority of his manufacturing to Italy. His made in Italy suits now are supposedly made by a reputable Italian suit maker and are fullly canvassed. You can see it in the broader lapels and softer shoulders in his suits.