Continuity has never been a high priority on Family Guy. Case in point, Meg has been portrayed as being friendless in some episodes, but she will have friends in others.
To add on: There has to be reason. I'm guessing Brian might have tried again with Quagmire and Quagmire could've been set off again which leads Brian to drink.
Exactly. I highly doubt that the Quagmire/Brian thing is going to come up in this episode at all, much less be referenced in any future episodes. Family Guy has never been continuity-heavy.
Usually as a cutaway gag or some equally non-canonical subplot or gag, with maybe one or two exceptions. Quagmire's contrived hated or Brian just feels like something that will be referred to once or twice and never again.
For anyone expecting any references to the last episode, or even a cameo by Jerome, it's not happening. Production wise, this episode takes place right before "Jerome Is The New Black".