Why such misery in the pool?
Who have broken node luck at the pool?

Yup, noticed that too...

hmm - i can not do anything to improve luck... we had extremely good (10-20% better) for two weeks in a row, now its bit worse but it means it should be better again soon

From servers perspective everything looks good. i have 6 backend servers which are loaded 2-5% max
feeleep