ChaCha20-BLAKE2b faster than ChaCha20-Poly1305

[samuel-lucas6]

Should it be possible for ChaCha20-BLAKE2b as an AEAD to be faster than ChaCha20-Poly1305?

I expected it to be slower than ChaCha20-Poly1305 in all cases, but quick BenchmarkDotNet benchmarks suggest it's faster than ChaCha20-Poly1305 on my machine for 16-64 KiB buffers. The benchmark code is the same, I've tried changing the benchmark code, sodium_init() should be getting called, and the results are similar for two different .NET libsodium bindings.