Marlon Bain's letters to Steeply (pp. 1047–1048)
The supposed cause of their separation is that Dr. Incandenza began using her in his work more and more extensively and eventually asked her to perform in the prenominate completely radical new type of filmed entertainment that supposedly was driving him to a breakdown. They supposedly became close, James and Jo-Ellen, though Orin in my judgment is not a reliable source of information about their relationship.
Context
Joelle's casting in the Entertainment, in the same epistemic fog: "supposed," "supposedly," "supposedly" — three hedges in two sentences, plus a source-reliability warning on Orin. The production history that 178 and n080 give from inside (auto-wobble lens, the apology monologue) exists out here only as gossip with the modality showing. "The prenominate completely radical new type of filmed entertainment" is as close as the outside world gets to naming Infinite Jest (V?).