Lyra2v2 is problematic for nvidia, the miner itself reports 30% higher hashrate than actual. Perhaps you should add a penalty for the algorithm on nvidia or check what miner gives a real hashrate.
just checked, and I seem to have the same problem..
both ccMinerAlexisHSR and ccminerPolytmos seem to report 30-50% more LYRA2V2 hashrate than the pool reports. this is on a clean 5.0 release install.
I'm sure there is a better real fix for this, but in the meantime if reduced all the numbers in the stats folder for the 4 lyra2v2 miners by half -- it was always stuck on that algo before.