My reaction and opinion:
Lindsey had been discussing in several interviews his work as a Producer/arranger on her songs (such as Dreams). I think that has offended her fan base, and maybe Stevie herself. Complaints have surfaced about too many "overdubs" or "over production." Somehow this is getting perceived as "taking credit" for the success of her songs. Stevie clearly has the creative idea (lyrics, melody, etc.), and Lindsey has always fashioned her music into a "song" on FM projects. But Lindsey has never received any song writing credit with Stevie (the two notable exceptions being Frozen Love and The Chain). I get the impression that Stevie wants to prove that she can have successful songs without Lindsey (again, my perception and my opinion).
From Lindsey's perspective, as Richard Dashut acknowledged, Lindsey never received Producer status until later in his FM tenure, even though he was calling the shots. The fallout with Ken Caillat may have come from him attempting to claim more credit than he was due on the musical production on Rumours.
So this appears to be a lot of people "explaining" their role in the success of FM music and legacy, as well as (perhaps) some "revisionist" history. It is truly unfortunate. As Harry Truman once said (paraphrasing), "It's amazing what can be accomplished if no one cares about who gets the credit." Admittedly, I am an LB fan (hence my moniker), but I really enjoy Stevie's songs on which Lindsey has worked (Twisted is an example). It is unfortunate that we may never have that again.