Theory:Doctor Who television discontinuity and plot holes/Spyfall


 * The Master says he took a trip home to Gallifrey in its "bubble universe," although it is established in Hell Bent that Gallifrey became unfrozen from another dimension and returned to the real universe, though at the extreme end of the time continuum.
 * It is unclear if the Master was aware of it becoming unfrozen so as far as he's concerned, it was still in a bubble universe.
 * Since he was taken back to the last day of the Time War in The End of Time, he was there when it was frozen and later unfrozen, and thus he knew the planet's status & location before getting a new TARDIS and being "kicked out," information backed up in The Doctor Falls.
 * It may have been returned to its 'bubble universe' afterwards. Or the Master may simply be referring to its former state. Or - as I think - he may have gone there when it was still hidden, perhaps through a confession dial? Did anyone notice that the device he used to send the Doctor his message looked awfully like one? Perhaps he was also asked about the Hybrid. Would make sense.