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 has stated.

In a normal (unscratched) session, the players create paradox clones of themselves through ectobiology and go back in time to the point of their "births" through Skaia's defense portals during the Reckoning to become the players who play the game. If the players scratch their session, the Paradox Clones are sent to opposite points in time by Skaia when they pass through its defense portals, creating a new timeline (e.g. the kids were sent before their own guardians in the post-scratch version of Universe B). However, in a glitched session the players are not created in the pre-scratched 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, 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 hinted that causing a scratch in a glitched session allows Lrd English to be summoned in the reset universe, and he is suggested to be responsible for the glitch occurring in the first place.

The only confirmed session affected by the glitch is the pre-scratch Beforus session in Universe A, whose 12 players would become the ancestors on post-scratch Alternia.