During a Banjo Kazooie stream, they start impersonating Rick Grimes, including reciting his three questions. This involves them attributing the phrase "Not good enough" to him when someone fails to answer his three questions appropriately. In the show, this has never been the case, and the line was never said by Rick.
Black Sheep Hit/Creator Backlash: Viet Crystal is their most-viewed series, and the one that drew many people to them. It is also their most requested series, to the point that they have gotten largely sick of hearing about it. This response is part of the reason they decided to move exclusively towards livestreaming.
Chinese Emerald also qualifies, though not to the extent of Viet Crystal, as they have expressed some interest in livestreaming the rest of it at some point in the future.
Development Hell: Viet Crystal. The series being produced depended mainly on Bert and Dubz having time to record together, which quickly led to month-long gaps between episodes. The most recent (and presumably last) episode was put up two years and two months after the original episode. A variety of factors, such as the move to livestreaming and Bert's departure from the channel, have ensured that the series is basically over. They have gone on record saying they will only return to fight Red if the original episode reaches 1 million views.
Fan Nickname: When Dezz misspelled "Zeus" during the Pokemon Green livestream, he earned the nickname "Dezzlexic."
During the same livestream, one of the NPCs referred to the thin trees as "slenders." After a while of Slenderman jokes, someone in the chat came up with the name "SlenderBert."
Missing Episode: There are actually a couple different variants of this in DeliciousCinnamon videos:
Early in the Viet Crystal series, Bert lost the save file and had to redo everything up to Azalea Forest. None of this was recorded, but the only things that happened that were significant were 1. they hatched their egg and 2. two of their Pokemon switched genders.
In the middle of the Radio Tower section, Bert somehow stopped recording and forgot to continue recording. The next episode after this starts at Claire's Gym.
Bert has also mentioned an unrecorded Level Grinding session where he leveled up his Haunter by battling a bunch of Gravelers that just ended up exploding, which didn't affect Haunter because it's a Ghost type.
In Episode 49 the video was lost but the audio remained.
In Kanto Episode 9, Bert accidentally reveals a save state in the Ruins of Alph, which was not visited in any of the previous episodes.
In the middle of their Criswelvania playthrough, Minecraft received an update, forcing them to restart their progress. They recorded a video of this, but they made it unlisted and added a link just for those who were curious.
Their YouTube livestream was apparently never archived.
Their second Pokemon Bootleg Green stream is gone due to own3d.tv shutting down.
Due to Twitch's August 2014 updates, most of the footage from their previous livestreams is gone forever.
Keep Circulating the Tapes: One fan was able to archive all of their Twitch material, and Dubz and Minimoose have stated that they planned to upload most of the footage on their DeliciousVlog channel.
All of their stream footage from livestream.com is gone as well.
A few of the hitbox streams, such as the first stream of Trine, are lost forever.