SharePoint Online PDF Viewer changed and performs very slowly now

Hello,

Our users noticed a change when viewing PDFs in their SharePoint Online document library. Occurred Monday 4/8/24.

They have it set up where when you click on the document from the library, it brings it up with the SharePoint Online PDF Viewer, it does not open in a new tab, and that's the way we prefer. With the viewer, you can click on the info button to bring up the info pane on the right, and you can edit your metadata from there.

They noticed several things.

-The background is now black, like in a dark mode, thats what initially tipped them off that something has changed.

-The info button is no longer available, it is now buried in the ... menu on the top left.

-It is now EXTERMELY slow to load. When they click on the next arrow to view the next PDF, it is very slow to load and also the info pane is very slow to load.

-When they filter or sort the library, and then start viewing the PDFs, it does not bring them up in the same order as the filter/sort. It's completely different.

I as the IT admin, have tried many things to improve performance, here's some notes.

-Not everyone has this new viewer experience. The older experience has a white background, and also the info button. See screenshots to see the difference.

-I am able to reproduce the slowness on other test pcs, though there are a few that seem to load fine.

-I have cleared browser cache, cookies

-Tried with different user accounts

-Tried with private browsers, and tried with Edge Firefox, and Chrome.

-Tried using a hotspot to be on a different network

I have opened up a ticket to Microsoft, but no response yet. I have also not seen any announcement of this change.

Has anyone else noticed this? Any workarounds or suggestions? Any way to roll back to the old viewer? (wishful thinking). I'm wondering if laptop specs are factoring in, which would surprise me because it's basically just web browsing here.

Thanks!
nick