WOT, but you don't say what year the Honda is. Weight is about 600 lb,
not 475 for most years.

That said, check tire pressure, low pressure in tires causes them to
heat up more, more heat leads to faster wear.

Hard to read the picture. I guess loose bearings, under inflated, out
of balance. Have you checked the toe in and camber on the trailer?
Drive straight with trailer, stop and measure toe in and camber when
the motorcycle is on the trailer. Some of those teeny tiny tires are
not rated for very fast speeds. I had to replace an axle on my trailer
after a spinout. But this was a 3,500 pound axle, not a teeny tiny
axle/tire combination. It may be that the rating of the axle was
optimistic/unrealistic and did not handle the load or a bump once.
Overloaded like in a turn and hitting a bump could have bent the axle
causing permanent excessive camber which can eat up tires.

If the tires are cupping (that means treadblocks are worn in an on-off
pattern- one up, one down) it is likely due to the tires hopping- same
as the wear from bad shocks or struts.   Since most trailers don't
have shocks, that's probably what's going on- especially since you've
been carrying a lighter load.  Often, bias ply trailer tires which are
load rated will solve the problem.
Hope this helps.

Had the same problem once.  It's caused by wheel bearing hubs not tightened
and/or lubricated exactly the same from one side of the trailer to the
other.   One side drags just a little more than the other pulling trailer
ever so slightly sideways.  Over the miles this translates to uneven tire
wear.

Have your bearings checked and adjusted by someone who understands how
important this is.

TL