High Hashrate but low Shares

Why is this happening between Rig02 and Rig04?
Both rigs have the same GPUs with the same settings but Rig04 with more than the double hash rate from rig02 produces less shares?
All rigs have the same problem but between 02 and 04 is more obvious.
Rig02 produces 45 shares per MH/s and all the others are about 17-18 shares per MH/s.

Hello, I have the same weirdness here

Same problem. I will listen in on this

i will expain it here