Together with Lesley Joseph, the pair have been part of the comedy since its first episode in 1989, while they have been friends in real life for more than 50 years.
According to the Daily Mail, however, Robson and Quirke had a disagreement over plans to mark the show's 30th anniversary in 2019 and haven't worked together since.
"Both Linda and Lesley were saddened that Pauline didn't want to return to make a 30th anniversary episode," a source told the newspaper.
"Linda and Pauline used to be very close, less so Pauline and Lesley.
"I think Pauline resented the attention that Lesley got and it was very tense and difficult to navigate at times.
"Pauline wasn't approached about the Christmas special. The atmosphere on the set had previously become difficult, there were real and tense issues."
The last full series of the show aired in 2016. body check tags ::