The worst part about JCE-miner for Vega rigs is that it is so stable - that I feel so bad to shut down 600 hours uptime rig just to update the miner version. JCE, we need hot swap updates! LOL! 
Could you tell us which amd driver, config, algo, and hashrate you have? I'm very curious because last time I tested JCE-miner, it was very unstable! So I'm still running SRBminer with 4 vega 56, and it's very stable so far!
I'm also using JCE miner with great results on my 6x vega 56 rig.
6x Sapphire pulse vega 56 - 1408 core 905 mV. / 3 with 950 memory 900 mV & 3 with 900 memory
Radeon adrenalin 18.5.1 drivers
win 10 1803
Monero algo cryptonightv1
https://imgur.com/awMAjgt current hashrate around 11950 h/s ( pool is showing 11.7-11.9k per 24h)
Gpu config is
{ "mode" : "GPU", "worksize" : 8, "alpha" : 64, "beta" : 8, "gamma" : 4, "delta" : 4, "epsilon" : 4, "zeta" : 4, "index" : 0, "multi_hash":1936 },