Menachem Shmei,
“When the Alter Rebbe was freed from the Peter Paul Fortress before evening on Yud-Tes Kislev, 5559 (1798)”
I once heard from a Chabad source that he was freed before yud tes Kislev, but the Chabad holiday is celebrated on yud tes Kislev itself because he was accidentally delivered to the house of a misnagid who objected to and questioned him about chassidic beliefs (while serving him tea). And he was “rescued” from the clutches of this misnagid after dark. So the time spent with a misnagid was so odious that it was equivalent to being imprisoned falsely by gentiles?