See my comment on the pull request
(also note that Accepted/Rejected etc should rarely if ever be used, they should use "Difficulty Accepted"/"Difficulty Rejected" etc ...)
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This might come across as a silly question .. I was wondering why there isn't a discarded number for diff1shares? Perhaps hardware errors under the specific mining device are related to the discarded number?
I'm positive I'm missing something here, but just attempting to make the stats/calculations as accurate as possible
Discarded isn't shares, it's work, and when using stratum it's effectively meaningless (so it wouldn't really be of interest in the normal display)
Stale is probably what you mean ... which has "Difficulty Stale" ...