Same issue here, can't use /title set "Saint of the Firmament".

I also tried with "Saint Ascendant" see if that somehow fixed it, but the title is not recognized (" “Saint Ascendant” is not a valid setting.").

Like Tyo I believe this is due to the last minute change in titles.
I'm hoping that this issue will be fixed in 5.35 or earlier, and that title duplicates will be removed because it's honestly a bit silly...