Did D2 look completely different for anyone else yesterday? The game has been looking totally washed out for me since Beyond Light launched, but all of a sudden yesterday it looked completely different. Everything was deep and bold and rich.

Last night, at the Tower (Wall) I noticed a very slight increase to my framerate or some sort of smoothing? It is barely perceptible.

I think it has to do with the fact that they performed some background maintenance yesterday?

https://twitter.com/BungieHelp/status/1334527817506177025

I experienced what you did, with a twist. At some point in the week(or two?) leading up to Beyond Light during a time when they were doing background maintenance as well.
It is honestly one of the most downright surreal Gaming experiences I have ever experienced. I was out on Mars combining Resonant Stems to try and get the last 2-4 missing Nodes I needed for that wretched Triumph and Emblem "Warminded".
While I was playing normally on Mars at first, at some point amid the long-session it felt like the game world (and graphical or lighting engine I'd surmise) all around me was being changed, updated, and deepened; While I was playing! It felt like when I turned the camera I was seeing updated, bolder, and richer colors, chroma rendering changes, deeper textures, shiny-er shaders, and bitmaps, around every corner. I think for sure, when I would travel through a loading zone into a new bubble, I was seeing wholesale changes with the building textures or decals happening or they had just snapped in during the (small)loading zone. Like you said everything was getting deeper, bolder, and richer, but before my very eyes it felt like.
Since then I do think I see at the Tower (Wall), the textures of the ground and walls seem deeper, bolder, and richer looking than they were before Beyond Light updates and maintenances.
I almost posted about it here the night it happened (a few days prior to Beyond Light), but when I re-read my post it sounded downright nutty. It felt like I licked a toad and forgot about doing it.

It feels good that the ongoing HDR growing pains were acknowledged through official channels. It would be great to hear more.

Do the film grain issues tie into the HDR problems? the grain feels like it's a static overlay sometimes (watch in fullscreen):

I first noticed the graininess or “noise” when they released that update that changed the way Orbs of Light looked, as well as the Shader UI (I think it was back during season of Opulence?). It doesn’t usually look as severe to me as it does in that clip you posted, but maybe I’m just desensitized to it.