The finding was an out-of-bounds read but Coverity does not realize the API takes a byte count, not element count. This change may produce the same finding.
Scrypt performance jumps as expected. For example, on a machine with 4 logical cores:
$ time OMP_NUM_THREADS=1 ./test.exe
Threads: 1
Key: DCF073537D25A10C9733...
real 0m17.959s
user 0m16.165s
sys 0m1.759s
$ time OMP_NUM_THREADS=4 ./test.exe
Threads: 4
Key: B37A0127DBE178ED604F...
real 0m4.488s
user 0m15.391s
sys 0m1.981s