In 7 years of ESO this is the first time I've ever seen a DF/BG bug this bad.
1. Pre-made group for a random normal. I am lead, we queue into FG2.
2. 1 DPS is trying to accept the dungeon quest, but it's the BG queue pop.
3. DPS is sucked into a BG - SOLO. He is still part of our group the entire time. Never removed. Can't talk in group chat tho.
4. DPS finishes BG and is back for dungeon final boss kill, gets random normal rewards.
Everyone in the group decided that either
A - BG finder should have dropped the DPS when he joined our group.
OR
B - BG finder should have failed to match DPS, because he was already in a group.
I've made a report in game, but felt this was weird enough for a forum report.