When output bytes is 48 rather than 256 as an argument for FSE_compressU16(), all generated bytes are identical up until 34 bytes. The rest of the bytes are clipped. The difference in code paths is that in the 34 bytes case, the non-fast path is chosen.
Repro:
When output bytes is 48 rather than 256 as an argument for FSE_compressU16(), all generated bytes are identical up until 34 bytes. The rest of the bytes are clipped. The difference in code paths is that in the 34 bytes case, the non-fast path is chosen.