get ahold of timney, let them know whats going on.
i had a problem with mine doubling once in a while when i first went suppressed. i was running 3oz carbine buffers at the time because i was previously shooting subs in my 16" 300 blackout upper unsuppressed.
they had me switch to a H2 buffer and send me a set of upgraded springs - trigger, hammer and disconnector - (mine are older timneys) and i've never had a problem since. they also included a red hammer spring to ensure ignition consistency with military grade primers too.
if i recall correctly - they said that when AR's are over gassed, the bolt carrier speed gets just a bit too fast & the disconnector spring just doesnt have time engage the disconnector to catch the hammer. so a quick spring upgrade (takes about 10 mins to take one apart and reassemble if you have any experience installing AR triggers) and a subtle buffer weight change and you're golden. you could also use an AGB.
timney gave me the option of doing the spring upgrades myself or sending the triggers in for service.
hth
