You actually might think this is a saber clash, but the Black Knights use whatever the same tech as their levitator cloaks/wings for their beam blades for one thing, and both the sparks and sound effects imply they are actually contacting armor to armor here despite the beam blade proximity. There's actually a shot where they imply beams crossing which just results in IJ losing an arm.

>>23373673
It's sort of iffy because how is the beam blade solid enough to bounce off of a shield still