More basic system here v2.2.2 W10 Pro 64bit v2004 on a 3GHz Intel Core2 Duo CPU and just WSJT running alongside N1MM with a K3 over the weekend.
Out of contests I run JTALert and DXLab suite (Commander/Log and Spot) so much more going on on the PC.
I've never noticed the decode light stay on before but it was doing it over the weekend during the Digi DX Contest. Didn't appear to lose me any decodes, other than them appearing after the next period had started from time to time.
I did have WSJT crash out on me twice though which it has never done before. Both times I had just logged a QSO and clicked on a decode of a wanted station - not his CQ but one containing reports. Think one of the decodes included a hashed call but not sure of the other occasion.