I've been observing some problems with sgminer 5.1.1-5-ga458 and the previous build during NeoScrypt mining.  It seems to happen when it automatically switches between Lyra2RE and NeoScrypt.  I'm mining on NiceHash and those two algos tend to be close to each other in profitability so it is not uncommon for the miner to periodically switch between the two.  However, in many occasions when the GPU switches to NeoScrypt after mining from another algo, NeoScrypt will cease to work.  All I get are a bunch of changing diff to a new value messages, but never any accepted shares.  And it may continue that way for hours and never switch to another algo.  If I manually restart the miner, it will immediately resume submitting accepted shares.  In other instances, my miner will freeze.  It won't report SICK or anything.  The screen just doesn't update.  But, I can press q to quit and it will say that it is exiting, but it never returns to the command prompt.  So, I have to reboot my whole computer.

Worst case scenario is that one GPU on a different machine has ceased to be able to mine NeoScrypt at all.  Didn't change anything in the settings.  Sgminer runs but just gives me a bunch of changing diff value messages.  I don't think it has anything to do with NiceHash because I have two other systems mining with the same settings and they are submitting shares, while the one in question just doesn't anymore.  I don't know if the GPU has been corrupted.

My NeoScrypt settings include:

"rawintensity" : "8192",
"gpu-engine" : "1150",
"gpu-memclock" : "1350",
"gpu-powertune" : "30",
"worksize" : "64"

And my temp never goes past 75C