During the meeting in the beginning of the episode, Frank's pencil switches numerous times from being a grey mechanical pencil to a yellow wood pencil.
Frank reveals that he was born on August 12th 1929, making him 75 in this episode. However, in the first series (set in 1994) he celebrated his 60th birthday, which would now make him 70.
When Geraldine is vesting for Christmas Eve Mass she is putting on a green stole. This is the wrong color for this time of year. Advent is purple and Christmastide is white. The priest has the option of using either color, but mostly they go with white. Green is for "ordinary time" which is around 8 January until Ash Wednesday and then picks up again the Sunday after Penticost and runs until the Sunday before Advent. This could be explained by her drunkenness.
Owen reacts positively to the news of Geraldine's alleged homosexuality, but he is equally delighted when she assures everyone that she isn't gay after all due to his feelings for her, which seems somewhat inconsistent.