We just had this happen 2-3 times in a row (we aren't sure the first time.) We had a full group in a Void Storm on Roche, Phobos (exterminate). Three of us were on PC, one guy on console.
First time, wasn't sure what happened, we were talking, thought maybe we forgot to make sure everyone had void traces. My son thought someone didn't get a reward. He thought was me, I thought was console guy with us.
Second time, I was one of the ones who got 10 traces, but didn't get to choose a reward. This also happened to console guy. We opened more relics just to see what happened for sure. I do have a SS, but it is just of a reward screen with no prime part or forma. I did choose a relic, did get 10 traces, chose a reward, and thought my name showed up under the rewards, my son thought mine was the one missing from rewards to chose. After mission, he was right, I had no reward.
Third time, we all posted in chat as we got 10. We all verified we had 10 void traces. We verified we had relics to open. Got to the reward screen, and the console guy couldn't choose a reward and his relic wasn't one we could choose, like he didn't choose a relic in the first place or didn't get enough traces. He verified he had chosen a relic, and left for the night.
Team was Rhino Prime, Mag Prime, Hildryn, Mesa Prime. The console guy was Hildryn, PC for the primes.
This is not a voidrig issue. (I was there for those.) We were tearing though corpus with melee. We were speed running those missions (hence the embarrassed thought we had missed someone getting traces the first time.) No one was in their necramech; no one had time to get one out.
EDIT: What we don't know is if we lost our relics. I didn't look to see how many I had after the first one as we were opening relics we had >20 to verify the bug.