Time echo

A time echo, or referred to as "Space Rabies" by Missy, was a mental blurring across time between different incarnations of a Time Lord, causing them to remember or forget certain events or conversations.

The various incarnations of the Doctor suffered from time echoes when they temporarily shed most of their symbiotic nuclei and lost part of their Time Sense, notably temporarily giving the Fourth Doctor knowledge about the Last Great Time War.

The incarnations of the Master also suffered from this, with Missy claiming to have been the one to accidentally infect the Doctor. (GAME: Lost in Time)