I was re-watching Clerks III and I picked up on an exchange between Randal and Dante that I'd missed in all my earlier viewings. While discussing what Dante thought of Randal's script, they say:
Dante: It's funny, but it was like my entire life flashed before my eyes.
Randal: My life flashed before your eyes.
Dante: I was glad you left some stuff out.
[Randal slightly nods to Dante]
I just realized that the stuff Randal left out was the Caitlin Bree stuff (from Clerks).
They left all that out because, in real life, the actress who played Caitlin Bree (Lisa Spoonauer) passed away of an accidental overdose of Hydromorphone in 2017 while she was battling cancer and lung disease, among other ailments. Additionally, Jeff Anderson, the actor who plays Randal, dated, and was briefly married to, Lisa Spoonauer in the mid to late 90's.
There are no references to the entire Caitlin story from the original Clerks in any of Randall's movie they are shooting.