Dumped it. In all 282 exceptions the region from the earlier wave's seek to the
first RIFF is exactly 12288 bytes: the seek chunk (240-260 bytes), then 47-57
non-zero trailer bytes, then zero padding out to the block size.
So an entry may hold a leading wave, a 12288-byte padded block, then its RIFF
wave -- and the assignment rule completes: first-or-second wave at/after the
entry offset is 7620/7620 = 100.00%, with ZERO unexplained.
This overturns my own refutation from one iteration ago. I proposed these were
leading segments, tested it as 'the seek should sit AT the first RIFF', got 0 of
282, and recorded the hypothesis refuted. It was right; my predicate was wrong
by exactly the padded block, a constant I had not yet found. A negative result is
only as good as the predicate it tests.
Still unidentified: what the 47-57 trailer bytes hold.
85548bf661