I think it is v4 problem. 1.8.1 is better than 1.8.0 but still not 100% stable. It was no problem on other algos in srbminer, eth rock stable, mined beam for weaks rock stable, everything i was trowing at vegas just worked. Then it came v4 and it came problems. I just love srbminer cause it is best miner for vega cards, but when v4 cam and it was unstable, i tried other miners for v4, you have at lleast 4 of them, and they crash even faster, teamredminer crashed under 10min on same settings as srbminer. Tried  to underclock gpu,mem for stability and same. Problem is only on v4, other algos are fine Something is very bad with new algo, just put loop in bat file and it will at least run again when it crashes