Certain Algorithms especially Cryptonite Variants are very sensitive to compiler optimization
Most of the Cryptonite algorithms including UPX/2 are very sensitive to compiler optimization flags.

This had been proven to be true with linux GCC-10 onwards. The hash will not be generated correctly and thus resulting in 25% rejection rate.

If you are mining using cryptonite variant algorithm, please consider using GCC-9 and below. Alternatively you can set the crypto related C files to be compiled with -O2 flag to reduce the compiler optimization.

If you are using ubuntu, 20.04 lts provides gcc-9 by default (in build-essential). 22.04 lts provides gcc-11 so you need to manually install gcc-9 or change the compile flag to -O2 for crypto related file to ensure you aren’t mining air.