What "Trigger job" did you do on it? Did you make changes to the sear engagement surfaces? If so, that could absolutely be the problem. Re install the NFA lpk back in the rifle, function check it and shoot it. If everything works then you did something wrong in your trigger work.
I did a "15 min. trigger job" on my AR when I built it 3 years ago. Would I try that today on a new build? Hell no!
As hard as LPKs are to come by these days, I wouldn't advise doing a homegrown trigger job to anyone. Bubba gunsmithing is not something we ,as a community, can enjoy right now as a result of the shortage of parts to fix an OOPS.