The session glitch is a mysterious glitch that affects certain sessions of the game. It is connected to the arrival of Lrd English within a universe. So far, all that is known about the glitch is what Doc Scratch .
In a normal (unscratched) session, the players create paradox clones of themselves and their guardians through ectobiology who go back in time to the point of their respective "births" through Skaia's defense portals during the Reckoning. If the players scratch their session, the Paradox Clones of the players and their guardians are sent to opposite points in time by Skaia when they pass through its defense portals, creating a new timeline (e.g. the kids switched places in the post-scratch version of Universe B, where the guardians became the players, and the players became the guardians). However, in a glitched session the players are not created in the pre-scratch session, but rather in the post-scratch session. Exactly how this occurs is unknown.
The glitch triggers "an unfathomable cascade of misfortune throughout Paradox space". Glitched sessions also appear to be unwinnable; a group of players in such a session are said to have a failure "more comprehensive" and "more systemic" than just "simple inadequacy so common to young players of this game". The players' only option, besides accepting defeat, is to initiate a scratch and reset their universe. This is inevitable from the start, due to the fact that the scratched universe is necessary for their own creation.
The glitch is stated to be the "calling card" of Lrd English, and is the way he "reserves his place in a universe for later visitation". It is implied that activating a scratch in a glitched session allows Doc Scratch to spawn as the First Guardian of the player's planet in the reset timeline. This allows Lrd English to enter the universe using Doc Scratch as a host.