Audio keeps changing on it's own

Despite numerous searches, I cannot find anything to address a weird issue I'm having. Working in Davinci 17.2 Build 11. On a 2019 iMac running Catalina. Finishing the final sound mix on a feature project. Crossfades that I apply to audio tracks on the edit page, don't replicate in Fairlight. I'll play through once and it dissolves just as nice as you could want. But if I go tinker with something else and come back, it has magically disappeared. Same with doing fade ins and fade outs. Meaning I pull the little dot over to bring the sound in or out on a track--no matter if I do this on the Edit page or the Fairlight page. Again, sounds great. But if I make any changes anywhere along the timeline and come back, suddenly those fades are gone. I can still see them on the Edit page, but listening back the sound just pops on. If I go to the Fairlight page, said fade has now disappeared.

What am I missing? How do I definitively put in a crossfade, or a fade-in, fade-out, that I KNOW is going to be there when I go back. Or, God forbid, do a final render, only to discover as I'm screening for a client that random instances have just vanished and the mix sounds like garbage?

Fairlight provides several method of creating Fades and Crossfades.

(1) Effects Panel | Toolbox > Audio Transitions

(2) Timeline | Audio Clip | Fade In/Out handles

(3) Timeline | Layered Audio Editing | Crossfades defined via the Clip Fade handles

(4) Timeline | Fairlight menu > Batch Fade Settings and Apply Batch Fades
(Requires v17.2)

It's kind of relatable but not exactly the same for me. crossfades do replicate in the fairlight page (at first)

however, i do still notice a long persistent bug which ignores the crossfades sometimes (both dragging the "dot" and a rightclick-transition), while they are there visually. And like you said also don't render. which is really bad.

If i read your post you literally have it all the time? for me it's more random. but if it happens, the only way to fix it is to delete the transition and recreate it.