bad share from miner

[entak]

I am running a proxy with ~20 miners, most of them are working flawlessly. But there are two machines that time to time produce error message

Bad share from miner XXX

They do have some hashrate though (from avgSpeed field printout), so probably just part of its results are errors (can somebody confirm this?). They are two with the highest hashrate (Ryzen 2/3 family).

All the miners are running identical miner sw (xmr-stak), they just differ by number of threads and low-power-mode number (btw is this really obsolete parameter with randomx?).

Is this some configuration issue on miner/proxy side? Or something else which can be somehow fixed? Or should I even bother fixing it? :) If config of the miner/proxy helps, I'll be glad to post it.