Sometimes audio is duplicated

[DeadNews]

This only happens on some tracks.
Audio for eximple.
Duration: 00:04:18.142

After:
ReSamplerLib -i './01 - Cloud 9.flac' -o './+resampled/01 - Cloud 9.flac' -r 44100 -b 16
Duration: 00:04:18.142

After:
ReSamplerLib -i './01 - Cloud 9.flac' -o './+resampled/01 - Cloud 9.flac' -r 44100 -b 16 --dither
Duration: 00:08:36.285
This is this track, but 2 times in a row.

ReSampler is built with:
g++ -pthread -std=gnu++11 main.cpp ReSampler.cpp conversioninfo.cpp -lfftw3 -lsndfile -o ReSampler -O3 -lquadmath -DUSE_QUADMATH
or this:
g++ -pthread -std=c++11 main.cpp ReSampler.cpp conversioninfo.cpp -lfftw3 -lsndfile -o ReSampler -O3 -DUSE_AVX -DUSE_FMA -mavx -mfma
result is the same

[jniemann66]

I know this is old, but I will check it out. Thanks for providing sample file to test.