While minting when the client finds a kernel (an output allowed to create a block) it tries to combine other outputs from the same address that are not allowed to mint (because they don’t have the 10k minimum amount requires).
Then it tries to make as many 10k outputs as possible. For example if you have 33k as total input there will be 2 outputs with 10k and 1 output with 13k. 10k is the default because it’s the minimum amount allowed to mint. You can change the split amount with the config/argument splitshareoutputs. The same process applies when sending NSR in normal transactions.
This process was removed and replaced by the one described above.